Add notification about ScalarDB 3.15.3 patch release; update/disable announcement bar

[josh-wong]

Description

This PR adds a notification message about the patch release of ScalarDB 3.15.3.

In addition, this PR removes the announcement bar message and adds a parameter to the announcement URL for better insight into usage.

Related issues and/or PRs

N/A

Changes made

• Added a notification message and link to the release notes for ScalarDB 3.15.3, the latest patch release.
• Disabled the announcement bar.
• Added parameters to the announcement bar URL.

Checklist

The following is a best-effort checklist. If any items in this checklist are not applicable to this PR or are dependent on other, unmerged PRs, please still mark the checkboxes after you have read and understood each item.

• I have updated the side navigation as necessary.
• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation to reflect the changes.
• Any remaining open issues linked to this PR are documented and up-to-date (Jira, GitHub, etc.).
• My changes generate no new warnings.
• Any dependent changes in other PRs have been merged and published.

Additional notes (optional)

N/A