game_join_processing.php: add news entry
game_join_processing.php: add news entry

Players joining the game will be announced as an admin news entry.

While this may have been overwhelming in the past, with our smaller
numbers it is very useful to be more aware when players join the game.

hemberger/smr,smrealms/smr,hemberger/smr,smrealms/smr,smrealms/smr,hemberger/smr,hemberger/smr