* enhancement: use reva client pool selectors
register mock service to registry and pass tests
* enhancement: bump reva
* Fix a couple of linter issues
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Co-authored-by: Ralf Haferkamp <rhaferkamp@owncloud.com>
This moves the lookup and the creation of the users' role assignemt out
of the user backend into its own interface. This makes the user backend
a bit simpler and allows to provide different implemenation for the user
role assignment more easily.
