Front end work to re-organize DB connections

[seancolsen]

Per the DB Connections Page Specs, we need the following changes.

Database page

• Remove this sidebar

  

Connections page

• Modify route

  • Old: /administration/db-connection/
  • New: /connections/

• Ensure the header navigation breadcrumb includes: the elephant and name, then the database switcher dropdown, then a "Connections" breadcrumb entry with the plug icon.

• Implement new page content design (Figma)

  

• Leave an empty placeholder modal for the "New Database Connection" form, as to be implemented in Front end changes for the "New Database Connection" form #3311.

• Re-organize components to better suit the new location of this page

• Navigation

  • Add "Manage Connections" link within the database switcher dropdown

    

  • Add "Database Connections" link within the top right menu

    

  • Remove "Database Connection" section from Administration navigation

    

Root route

• Modify redirection logic
  • Old: redirect to the database page for the connection with the highest id
  • New: If there is one and only one connection, then redirect to the database page for that connection. Otherwise, redirect to /connections/

Navigation header

• Simplify the elephant logo and "Mathesar" text alongside it.

  • Currently, it's a hyperlink with a dynamic href depending on the current page. For any pages within a database connection, it points to the database page, and for other pages it points to the root route.
  • Instead, it should always point directly to the root route. (No more dynamic behavior.) The navigation behavior when clicking it will then be subject to the redirection logic described above.

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Note

This ticket is labeled "frontend" because the majority of the changes here are strictly frontend changes. However it will also require a tiny bit of backend changes for the page routing adjustments.

[pavish]

The route modification:

- Modify route
    - Old: `/db/<connection_name>/`
    - New: `/db/<connection_id>/`

is spun into a new issue: #3328