Pipenet revamp

-Removed the pipenet network datum, now it will all be done with the pipeline datum
-All atmos pipes and machines will always have a pipeline datum
-Moved the valves to the binary subtype and the portable connectors to the unary subtype
-The pipe vents (who were barely used in three spots of the map) are removed, the map slots will replaced with outlets
-Fixes some bugs of pipenet disconnection, mostly on explosions
-Cleaned a bit the copypaste of construction.dm of pipes
-Removed the ID restrictions of digital valves and the frequency (both unused)

Gonna make a second commit for the map and try to fix any differences later.
This took me almost 14 hours.