Find a way to set quota on personal space

[rhafer]

As the "cs3" backend in graph doesn't support the OData filters yet, it is currently not possible to set quota on personal spaces.

Possible solutions:

• Add $filter support to the GetUsers implementation of the cs3 backend (requires changes on the CS3 users api)

or

• Allow browsing personal spaces via the Spaces view in the Admin panel an make it possible to set quota there (like it is already possible for project spaces)

[rhafer]

cc @micbar

[kulmann]

We'll opt for the second idea (personal spaces via spaces view in admin settings)

Web story: https://github.com/opencloud-eu/web/issues/1309

Needs personal spaces to be listed via graph api though.

[micbar]

Personal spaces are listed on the drives endpoint when the user has the permission. Normally the web client uses a filter for project spaces.