Prevent creating namespaces/orgs on pushes (CREATE_NAMESPACE_ON_PUSH)
if user is restricted.
Also updates RESTRICTED_USERS_WHITELIST to defaults to all if not set,
given that FEATURE_RESTRICTED_USERS is set.
- Similar to LDAP_SUPERUSER_FILTER, add a specific filter to define
restricted users, based on the LDAP_USER_FILTER
- restrict writes on restricted users' own namespace. Normal
permissions applies on organization membership
- add global readonly superuser GLOBAL_READONLY_SUPER_USERS (PROJQUAY-2604)
- Removes RESTRICTED_USER_INCLUDE_ROBOTS, FEATURE_RESTRICTED_READ_ONLY_USERS
