API response for all projects a user has access to
Description
Premium customer would like to retrieve the data from GET admin/users/<user>/projects
via the API.
They would also like the access level to be displayed.
Proposal
Two requests would be okay, for example /users/:id/member_projects
and /users/:id/member_groups
Links / references
ZD: https://gitlab.zendesk.com/agent/tickets/88949 (Internal only)