Implement team provider api

[juliushaertl]

Resolves #43683

Teams are considered evolution of circles where we now want to aggregate all resources that are related (shared or owned) by a given team. Therefore we need a generic API so that apps that offer sharing to teams can expose the list of resources and teams for a given resource.

Example implementation can be found for deck and collectives already.

In the future we may extend this namespace to become a stable OCP/OCS API for other methods related to circles which for now is still bound to the classes in OCA\Circles.

ToDo

• Verify team membership
• API documentation (openapi, phpdoc, dev docs)
  • phpdoc: Define that resources should be returned in order of importance (e.g. folders before files)
  • phpdoc: Clarify order of icons
  • OpenAPI spec
  • Developer docs

Provider implementations

• Collectives feat: Implement a team resource provider collectives#1130
• Deck feat: Implement a team resource provider deck#5625
• Files sharing
• Groupfolders
• Talk
• Others?

[blizzz]

just some detail findings (that partly I would have expected to be found by CI). In general, everything is layed out fine 👍

[provokateurin]

OpenAPI LGTM

[provokateurin]

OpenAPI is good

[juliushaertl]

Cypress failure is unrelated

[joshtrichards]

Does this mean we need to add the Circles app to alwaysEnabled (as a shipped app) due to the tight coupling? (#45484 brought this up today).

[blizzz]

Does this mean we need to add the Circles app to alwaysEnabled (as a shipped app) due to the tight coupling? (#45484 brought this up today).

One way to solve it, I'd rather say we need a NullProvider sort of things, provided it does not lead to odd effects/assumptions.