Fix vector search and ABAC titles in sidebar navigation and re-order them

[josh-wong]

Description

This PR revises the titles of the new vector search and attribute-based access control (ABAC) docs in the sidebar navigation and moves them to the Advanced Configurations subcategory.

In addition, this PR moves encryption-related docs to the Advanced Configurations subcategory.

Related issues and/or PRs

• Docs originally added in Add ScalarDB 3.15 docs #980.

Changes made

• Changed the title of the vector search and ABAC docs in the sidebar navigation.
• Moved the following docs:
  • The vector search doc from Develop > References to Develop > Run Transactions > Advanced Configurations and Operations.
  • The ABAC doc from Develop > References to Develop > Run Transactions > Advanced Configurations and Operations.
  • The two encryption-related docs from Develop > References to Develop > Run Transactions > Advanced Configurations and Operations.

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