cbcollect_info to use an internal RBAC

Background

We have seen the odd case in the pass where running cbcollect_info has cause issues.

Problem

Debugging these cases can be hard as there is no much information about what cbcollect_info is doing at any one time (we have improved his) and we can't cross reference requests from cbcollect_info against the other logs.

Suggest

With the addition of RBAC, we could take advantage of the logging that already exist by using a special cbcollect_info user instead of reusing the _admin user that is shared with ns_server.