Creation of a sharing controller about cozy-data-system

[nono]

Maybe, it's better to call it 'sharing service' instead of 'sharing controller', as controller has a specific meaning in cozy.

[frankrousseau]

I think @Gara64 talks about Express/Americano controllers.

[frankrousseau]

But on the architectural point of view, we could include it as a service like we talked for files.

[paultranvan]

Yes, I meant an Americano controller, but this could indeed be viewed as a service.