Endeavour deck 3 portside tweaking (#6928)

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## About The Pull Request

Adjusts the areas around Cargo on Deck 3 to enable more hidden movement
through that section of the ship, and removes an unnecessary dorm around
Cargo to add more maints area and gimmicks.
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## Why It's Good For The Game

Re-enables hidden movement and semi-hidden movement from areas around
the cargo area, and into the middle and starboard sides from the port
side aft of Deck 3 to the middle.

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## Changelog

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:cl:
tweak: moved areas around in cargo, made less cavernous entrance lobby
in line with other departments.
fix: reconnected disposals loop to mail room, entire system bypassed the
mail room
remove: gimmick cludge shuttlecraft bay, walled in for a maints
room/loot.
tweak: moved mining prep area out of the corner it was in, and stretched
it slightly to remove the sense of crampness.
add: small maints 'tool room' behind mail room, with salvageable
machines and frames for building new ones.
add: small gimmick room next to cargo, forward of the lobby.
add: one small maints dorm, right next to the vault, an homage to a
'payday' heist that was interrupted before the ship was delivered.
add: more maints spaces. 
remove: excessive tritium, specialist tox and oxy med kits from cargo
prep area
tweak: reduced size of q-pad room, was too large for no particular
reason
remove: three redundant lounge areas from cargo - 1 from in front of
QM's office, 1 from break room, one from excess hallway in front of mail
room.
tweak: shifted mail room forward to remove extra hallway from in front
of cargo.
/:cl:

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