Adds tabs to maven registries and upstreams page

What does this MR do and why?

Adds tabs to maven registries and upstreams page

Adds Registries and Upstreams tabs with query params synced.

Emit registries count from existing registries list view and show them in the tab.

Temporarily emit count from new upstreams list view.

Move files to structure similar to the backend and other registry directories.

Update Maven upstreams breadcrumb to use tab query parameter.

Update redirect path when upstream is deleted.

Inject edit & show upstream template links to be used in upstreams list component in next iteration.

Fix sidebar menu not active on registries and upstreams page. This was introduced in Replace registries index with registries and up... (!205144 - merged)

EE: true

References

• Design: #556837[UpstreamsList.png]

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Ensure you have enabled the following feature flags

$ gdk rails console
Feature.enable(:maven_virtual_registry)
Feature.enable(:ui_for_virtual_registries)

2. Go to a top-level group
3. Go to Deploy -> Virtual Registry
4. Create a new maven registry
5. Then click on the Maven registries breadcrumb to see the Registries and Upstreams tabs.
6. Confirm empty state is shown under the upstreams tab.
7. Confirm that sidebar Virtual registry tab is active.
8. Click on the newly created maven registry
9. Click on the Add upstream button
10. The required fields are name, url. For the URL, you can use https://repo.maven.apache.org/maven2
11. Click on Create upstream
12. Visit the upstream details groups/<group>/-/virtual_registries/maven/upstreams/<upstream-id>
13. Confirm that Maven upstreams breadcrumb shows the Registries and upstreams page with Upstreams tab selected.
14. Visit the upstream edit page groups/<group>/-/virtual_registries/maven/upstreams/<upstream-id>/edit.
15. Confirm that Maven upstreams breadcrumb shows the Registries and upstreams page with Upstreams tab selected.

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #556837 (closed)