Fixes #5911 - perms for system registration calls

Also handles env lockin/cv lockin for content view remove

Rules of the Game
To register a system one needs
1) create_content_hosts (under content hosts resource)
2) view_content_views
3) view_environments

Also cleaned out some old code.
Merge pull request #4147 from parthaa/sys-registration

Fixes #5911 - Added permissions for content host registration calls