Harbor quota feature

[thcdrt]

Hello,

Is your feature request related to a problem? Please describe.
It's not a problem, it's a feature I would love to have in Harbor. Currently it's possible to configure quotas per project. As an administrator I would like to be able to configure a quota shared by all projects. It would be a global quota.

Describe the solution you'd like
It could inspire from project quota feature, to have middleware that prevent users to push Docker images layers/manifests when storage quota is reached.
When approaching of the quota (90%), it could display a warning message of the same type that when the registry is RO.
The used space / quota should be displayed somewhere in the UI (In project quotas page that would be renamed ?)
The quota could not be modified inside the UI, it should be configured in the Harbor configuration file only.

Describe the main design/architecture of your solution
Maybe we could reuse project quota architecture ?

Describe the development plan you've considered
Nothing for now

Additional context

[thcdrt]

@qnetter

[thcdrt]

Linked to #16671