Some menu tweaks
I added a tip message to the login menu that explains how and where the client can create an account (addresses 0004359). It also adds that if a server host is using their own authentication host (i.e. authhostname
isn't "auth.zandronum.com"), then the client should register there instead.
I also shortened the length of the lines of the warning message for backup commands in the network options menu, and added indentation to some of the menus so that items are centred in the middle of the screen better.