[Manual Backport 2.x] Add release notes for 2.11 (#10594)

[noCharger]

Signed-off-by: Louis Chu [email protected]
(cherry picked from commit 382eb30)

Description

[Describe what this change achieves]

• [Manual Backport 2.x] Add release notes for 2.11 (Add release notes for 2.11 #10594)

Check List

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[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/27775/
• CommitID: 6eeb7c4
  Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
  Is the failure a flaky test unrelated to your change?

[github-actions]

Compatibility status:

Checks if related components are compatible with change 6eeb7c4

Incompatible components

Incompatible components: [https://github.com/opensearch-project/performance-analyzer.git, https://github.com/opensearch-project/ml-commons.git]

Skipped components

Compatible components

Compatible components: [https://github.com/opensearch-project/security-analytics.git, https://github.com/opensearch-project/security.git, https://github.com/opensearch-project/custom-codecs.git, https://github.com/opensearch-project/geospatial.git, https://github.com/opensearch-project/index-management.git, https://github.com/opensearch-project/notifications.git, https://github.com/opensearch-project/sql.git, https://github.com/opensearch-project/job-scheduler.git, https://github.com/opensearch-project/neural-search.git, https://github.com/opensearch-project/observability.git, https://github.com/opensearch-project/k-nn.git, https://github.com/opensearch-project/cross-cluster-replication.git, https://github.com/opensearch-project/alerting.git, https://github.com/opensearch-project/anomaly-detection.git, https://github.com/opensearch-project/asynchronous-search.git, https://github.com/opensearch-project/common-utils.git, https://github.com/opensearch-project/performance-analyzer-rca.git, https://github.com/opensearch-project/reporting.git]