Tenancy Based Access Control - User Resource

We have recently added "tenancy" to the project.
With tenancy, every resource have a tenant, where resource can be a delivery-service, a server (future) and even a user.
We are now starting to enforce access-control based on the resource tenancy. A user can manage a resource only if the resource is under the user tenancy.

This JIRA deals with "user as a resource". We enforce access control via the API to the different users.
We also add a naive change in the UI - presenting the logged in user only users he has access to.