Backport "docs: Extend the documentation for OpenSearch Dashboards"

[siegfriedweber]

Description

Backports #77 "docs: Extend the documentation for OpenSearch Dashboards" to the release-25.11 branch

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

Author

• Integration tests passed (for non trivial changes)
• Links to generated (nightly) docs added
  • https://docs.stackable.tech/home/25.11/opensearch/getting_started/first_steps/#_using_opensearch_dashboards
  • https://docs.stackable.tech/home/25.11/opensearch/usage-guide/opensearch-dashboards/

Reviewer

• Code contains useful comments
• Code contains useful logging statements
• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

• Feature Tracker has been updated
• Proper release label has been added
• Links to generated (nightly) docs added
• Release note snippet added
• Add type/deprecation label & add to the deprecation schedule
• Add type/experimental label & add to the experimental features tracker

[labrenbe]

lgtm