RDoc-3958 + RDoc-3879 [Per-feature reorganization] Per-database and Server-wide Connection strings

[Danielle9897]

Issue links

https://issues.hibernatingrhinos.com/issue/RDoc-3958/Per-feature-reorganization-Connection-strings
https://issues.hibernatingrhinos.com/issue/RDoc-3879/Server-wide-connection-strings

Additional description

• Created a new menu item, Integrations > Connection Strings,
  as the home for per-database and server-wide connection string articles.
• Added new documentation for per-database and server-wide connection strings.
• Moved the existing connection string articles from ../client-api/operations/maintenance/connection-strings to the new location.
• Added links from task articles that use connection strings to the new per-database and server-wide connection string docs, so readers can choose whether to define the connection string at the database scope or cluster scope.
• Added missing “add connection string” sections to task articles where connection string setup was not documented.

Type of change

• Content - docs
• Content - cloud
• Content - guides
• Content - start pages/other
• New docs feature (consider updating /templates or readme)
• Bug fix
• Optimization
• Other

Changes in docs URLs

• No changes in docs URLs
• Articles are restructured, URLs will change, mapping is required (update /scripts/redirects.json file, set Documents Moved PR label)

Changes in UX/UI

• No changes in UX/UI
• Changes in UX/UI (include screenshots and description)