[couchbase] Add Integration Package with Database Stats Data Stream

[kush-elastic]

• Enhancement

What does this PR do?

• Generated the skeleton of Couchbase integration package.
• Added 1 data stream ( database_stats )
• Added data collection logic.
• Added the ingest pipelines.
• Mapped fields according to the ECS schema and added Fields metadata in the appropriate yml files.
• Added system test cases.
  Note : This PR won't include dashboards. The dashboards for sync gateway will be included in the upcoming PRs.

Checklist

• I have reviewed tips for building integrations and this pull request is aligned with them.
• I have verified that all data streams collect metrics or logs.
• I have added an entry to my package's changelog.yml file.
• If I'm introducing a new feature, I have modified the Kibana version constraint in my package's manifest.yml file to point to the latest Elastic stack release (e.g. ^7.13.0).

How to test this PR locally

• Clone integrations repo.
• Install elastic-package locally.
• Start elastic stack using elastic-package.
• Move to integrations/packages/couchbase directory.
• Run the following command to run tests.

elastic-package test

Related issues

• Relates [couchbase] Add Integration Package with Bucket Data Stream #3666
• Relates [couchbase] Add Integration Package with Cluster Data Stream #3706
• Relates [couchbase] Add Integration Package with Node Data Stream #3771
• Relates [Couchbase] Update manifest file for bucket data stream #3900
• Relates [couchbase] Add Integration Package with CBL Replication Data Stream #3947
• Relates [couchbase] Add Integration Package with Resource Data Stream #3971
• Relates [couchbase] Add Integration Package with Cache Data Stream #3982

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• Start Time: 2022-10-04T08:33:09.683+0000

• Duration: 68 min 59 sec

Test stats 🧪

Test	Results
Failed	0
Passed	36
Skipped	0
Total	36

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🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	100.0% (9/9)	💚
Files	100.0% (9/9)	💚 2.787
Classes	100.0% (9/9)	💚 2.787
Methods	100.0% (63/63)	💚 10.317
Lines	100.0% (923/923)	💚 8.474
Conditionals	100.0% (0/0)	💚

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[ManojS-shetty]

LGTM!