Technically, all you need for a DMAP is the .map file.
I would suggest keeping the darkradiant files, as those keep track of things like groups, layers and camera position and things like that.
BAK is a backup that DR makes of your .map file.
CM is collision (I think).
LIN file is for leaks which show a line in red in DR to where the leak occurred.
AAS files is for pathfinding for AI.
PROC file is from DMAP, you need that to play the map in game.