(docs) Bundle Deployment Configuration

Adds user-facing documentation for the Bundle Deployment Configuration feature,
which provides feature parity with OLM v0's `Subscription.spec.config` (SubscriptionConfig).

**What's included:**

- How to enable the `DeploymentConfig` feature gate
- Complete configuration reference for all deployment customization options:
  - Environment variables (`env`, `envFrom`)
  - Resource requirements (`resources`)
  - Node placement (`nodeSelector`, `tolerations`, `affinity`)
  - Storage (`volumes`, `volumeMounts`)
  - Annotations
- Migration guide from OLM v0's SubscriptionConfig to OLM v1
- Validation details including how the JSON schema is generated for registry+v1 bundles
- Troubleshooting and verification steps

**Related work:**
- RFC: [Deployment Configuration (achieving feature parity with OLMv0's SubscriptionConfig)](https://docs.google.com/document/d/18O4qBvu5I4WIJgo5KU1opyUKcrfgk64xsI3tyXxmVEU/edit?usp=sharing)
- Implementation:
    - #2454 (schema generation and validation)
    - #2469 (renderer support)
    - #2482 (controller integration)
    - #2527 (DeploymentConfig feature gate)

This documentation is placed in `docs/draft/howto/` as the feature is currently `experimental`
and requires the `DeploymentConfig` feature gate to be enabled.

Author: anik120

docs/draft/howto/configure-bundles.md

@@ -1,7 +1,7 @@
 ## Description
 
 !!! note
-This feature is still in `alpha` and the `SingleOwnNamespaceInstallSupport` feature-gate must be enabled to make use of it.
+This feature is still `experimental` and the `SingleOwnNamespaceInstallSupport` feature-gate must be enabled to make use of it.
 See the instructions below on how to enable it.
 
 ---