Rename facia classes to stop clashing when compiling

Since facia-tool is dependant on admin (For now!), and we copied admin, there are some clashing classes in teamcity.

Update:
This now is all done in one step. All of the facia tooling has been removed from admin. The dependency on admin by facia-tool has been removed, and the Authentication class has moved with all its bits to common. I have renamed this AuthAction and kept the Authentication object local in admin; companion objects need to be in the same file.

I have kept the Login object in admins authentication.scala, as this is localised to Admin and its request scope. There is a copy of this class also in facia-tool (authentication.scala), the reason for this is that we will be changing how Auth works in facia-tool.