Enforce strict order for permission determination

The order of permissions defined within a user or team is preserved
during read and write.  This order is important for determining the
regex match used within the user or team object.

If the user is an admin or repository owner, then RW+
Else if user has an explicit permission, use that
Else check for the first regex match in user permissions
Else check for the HIGHEST permission from team memberships

If the team is an admin team, then RW+
Else if a team has an explicit permission, use that
Else check for the first regex match in team permissions