Move Storage App to Core: initial frontend

What does this MR do and why?

This is the first MR for Move storage app to CE (#371824 - closed). Here we are making some backend and initial FE changes to move the storage Usage Quotas tab to the Core codebase so that the view is available for Community Edition.

Here we're focusing on Group Usage Quotas.

MR Cadence

Description	MR
Move :read_usage_quotas policy to Core app	!103021 (merged)
Create Usage Quotas route/controller/view in Core	!102906 (merged)
Add menu entry on sidebar	!106083 (merged)
Create usage quotas Vue app	!107359 (merged)
Reorganize Backend code for storage tab	!109806 (merged)
Move Storage App to Core: initial frontend	👈 you're here
Move storage app to Core: namespace vue app	!108333 (closed)

Screenshots or screen recordings

For this MR there are no UI changes, so you can check the screenshots in this other MR.

How to set up and validate locally

We need to validate this in 4 scenarios:

1. GitLab EE: by having a test license in your GDK.
2. GitLab SaaS: setup a license like the above and simulate SaaS
3. GitLab EE Unlicensed: by removing your license in http://gdk.test:3000/admin/subscription
4. GitLab CE: by executing
   1. export FOSS_ONLY=1
   2. gdk restart
   3. Tanuki gdk website icon (the one in the browser tab) should be blue, then you're in CE

Now go to any Group Usage Quotas: http://gdk.test:3000/groups/flightjs/-/usage_quotas and check if your local setup matches the screenshots.

• To enable the FF: Feature.enable(:usage_quotas_for_all_editions)
• To disable the FF: Feature.enable(:usage_quotas_for_all_editions)

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.