opensearch: Add repository-azure plugin

[siegfriedweber]

Add the repository-azure plugin to the OpenSearch image. This allows snapshots to be stored in Azure Blob Storage and enables Azure as a backend for remote-backed storage.

Tasks

• feat(opensearch): Add the repository-azure plugin #1689
• test: Test the repository-azure plugin opensearch-operator#194

[siegfriedweber]

Release Notes

Platform improvements

OpenSearch

The OpenSearch image now ships the repository-azure plugin. Azure Blob Storage can be used as a snapshot repository and as a backend for remote-backed storage.