Provide Read-Only Access to Crowd Admins

Problem Definition

It's not possible to give read-only access to Crowd administrators.

Suggested Solution

Add option to tell if a group has read-only access to the application or not, which would allow users to set the group with administrator permissions if needed.

Why this is important

In some cases, administrators want to give read-only access to the applications, and at the moment Crowd doesn't allow this for administrator users.