[receiver/vcenter] Adds additional resource pool metrics (open-telemetry#33741)

**Description:** <Describe what has changed.>
<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
The following PR adds these
[metrics](https://vdc-repo.vmware.com/vmwb-repository/dcr-public/d1902b0e-d479-46bf-8ac9-cee0e31e8ec0/07ce8dbd-db48-4261-9b8f-c6d3ad8ba472/vim.ResourcePool.Summary.QuickStats.html)
```
- vcenter.resource_pool.memory.swapped
- vcenter.resource_pool.memory.ballooned
- vcenter.resource_pool.memory.granted {memory_granted: shared / private}
```

It also adds the attribute `memory_usage_type` and splits up the
`vcenter.resource_pool.memory.usage` metric into the following
attributes: `host, guest, overhead`

**Link to tracking Issue:**  open-telemetry#33607

**Testing:** <Describe what testing was performed and which tests were
added.>
Golden files were generated to show the addition of the new metrics.

**Documentation:** 
Documentation generated by `make generate`.

Author: BominRahmani

.chloggen/add-vcenter-resource-pool-metrics.yaml

@@ -0,0 +1,30 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: vcenterreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: "Adds additional vCenter resource pool metrics and a memory_usage_type attribute for vcenter.resource_pool.memory.usage metric to use."
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [33607]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: |
+  Added "vcenter.resource_pool.memory.swapped", "vcenter.resource_pool.memory.ballooned", and "vcenter.resource_pool.memory.granted"
+  metrics. Also added an additional attribute, "memory_usage_type" for "vcenter.resource_pool.memory.usage" metric, which is
+  currently under a feature gate.
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

receiver/vcenterreceiver/README.md

@@ -55,3 +55,12 @@ The full list of settings exposed for this receiver are documented [here](./conf
 Details about the metrics produced by this receiver can be found in [metadata.yaml](./metadata.yaml) with further documentation in [documentation.md](./documentation.md)
 
 ### Feature gates
+
+**ALPHA**: `receiver.vcenter.resourcePoolMemoryUsageAttribute`
+
+The feature gate `receiver.vcenter.resourcePoolMemoryUsageAttribute` once enabled will enable the memory usage type attribute for 
+the `vcenter.resource_pool.memory.usage` metric.
+
+This feature gate will eventually be enabled by default, and eventually the old implementation will be removed. It aims
+to give users time to migrate to the new implementation. The target release for this featuregate to be enabled by default
+is v0.106.0.

receiver/vcenterreceiver/documentation.md

@@ -283,6 +283,12 @@ The usage of the memory by the resource pool.
 | ---- | ----------- | ---------- | ----------------------- | --------- |
 | MiBy | Sum | Int | Cumulative | false |
 
+#### Attributes
+
+| Name | Description | Values |
+| ---- | ----------- | ------ |
+| type | The type of memory usage. | Str: ``guest``, ``host``, ``overhead`` |
+
 ### vcenter.vm.cpu.usage
 
 The amount of CPU used by the VM.
@@ -526,6 +532,36 @@ As measured over the most recent 20s interval.
 | direction | The direction of network throughput. | Str: ``transmitted``, ``received`` |
 | object | The object on the virtual machine or host that is being reported on. | Any Str |
 
+### vcenter.resource_pool.memory.ballooned
+
+The amount of memory in a resource pool that is ballooned due to virtualization.
+
+| Unit | Metric Type | Value Type | Aggregation Temporality | Monotonic |
+| ---- | ----------- | ---------- | ----------------------- | --------- |
+| MiBy | Sum | Int | Cumulative | false |
+
+### vcenter.resource_pool.memory.granted
+
+The amount of memory that is granted to VMs in the resource pool from shared and non-shared host memory.
+
+| Unit | Metric Type | Value Type | Aggregation Temporality | Monotonic |
+| ---- | ----------- | ---------- | ----------------------- | --------- |
+| MiBy | Sum | Int | Cumulative | false |
+
+#### Attributes
+
+| Name | Description | Values |
+| ---- | ----------- | ------ |
+| type | The type of memory granted. | Str: ``private``, ``shared`` |
+
+### vcenter.resource_pool.memory.swapped
+
+The amount of memory that is granted to VMs in the resource pool from the host's swap space.
+
+| Unit | Metric Type | Value Type | Aggregation Temporality | Monotonic |
+| ---- | ----------- | ---------- | ----------------------- | --------- |
+| MiBy | Sum | Int | Cumulative | false |
+
 ### vcenter.vm.cpu.readiness
 
 Percentage of time that the virtual machine was ready, but could not get scheduled to run on the physical CPU.

receiver/vcenterreceiver/go.mod

@@ -15,6 +15,7 @@ require (
 	go.opentelemetry.io/collector/config/configtls v0.104.1-0.20240705135726-e014c1ed756c
 	go.opentelemetry.io/collector/confmap v0.104.1-0.20240705135726-e014c1ed756c
 	go.opentelemetry.io/collector/consumer v0.104.1-0.20240705135726-e014c1ed756c
+	go.opentelemetry.io/collector/featuregate v1.11.1-0.20240705135726-e014c1ed756c
 	go.opentelemetry.io/collector/filter v0.104.1-0.20240705135726-e014c1ed756c
 	go.opentelemetry.io/collector/pdata v1.11.1-0.20240705135726-e014c1ed756c
 	go.opentelemetry.io/collector/receiver v0.104.1-0.20240705135726-e014c1ed756c
@@ -88,7 +89,6 @@ require (
 	github.com/yusufpapurcu/wmi v1.2.4 // indirect
 	go.opentelemetry.io/collector v0.104.1-0.20240705135726-e014c1ed756c // indirect
 	go.opentelemetry.io/collector/config/configtelemetry v0.104.1-0.20240705135726-e014c1ed756c // indirect
-	go.opentelemetry.io/collector/featuregate v1.11.1-0.20240705135726-e014c1ed756c // indirect
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.49.0 // indirect
 	go.opentelemetry.io/otel v1.28.0 // indirect
 	go.opentelemetry.io/otel/exporters/prometheus v0.50.0 // indirect

receiver/vcenterreceiver/internal/metadata/custom.go

@@ -0,0 +1,16 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package metadata // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/vcenterreceiver/internal/metadata"
+
+import "go.opentelemetry.io/collector/pdata/pcommon"
+
+func (mb *MetricsBuilder) RecordVcenterResourcePoolMemoryUsageDataPointWithoutTypeAttribute(ts pcommon.Timestamp, val int64) {
+	mb.metricVcenterResourcePoolMemoryUsage.recordDataPointWithoutType(ts, val)
+}
+
+func (m *metricVcenterResourcePoolMemoryUsage) recordDataPointWithoutType(ts pcommon.Timestamp, val int64) {
+	dp := m.data.Sum().DataPoints().AppendEmpty()
+	dp.SetTimestamp(ts)
+	dp.SetIntValue(val)
+}