feat(balance): revamp military bunkers

[chaosvolt]

Purpose of change

And the final major piece of the puzzle, various updates to military bunkers. Goal of making the old-school variant less of a loot piñata but also more consistent and varied in its spawns, bringing the other variant in line with the first variant balance-wise, and making it so the mix of well-defended military loot plus a decent shot at a military map to locate other locations is the primary draw of the location, rather than having a mech.

Describe the solution

1. Moved the itemgroups defined in the mapgen file for bunkers to the military itemgroup file.
2. Updated contents and weights of bunker_basement_loot, removing some itemgroups already used elsewhere and breaking the call to mil_armor up into relevant components not already spawned by bunker_basement_clothing. Gun spawns also favor military_specops_guns instead of just milspec rifles and launchers, so it alternates between standard fireteam guns and a wider variety of wacky milspec guns in general. Overall weights a bit more even and fit a total weight of 100. Total spread leans toward 30% guns/ammo/related, 30% armor and related standard accessories, 30% misc mil_hw, and 10% advanced military tech.
3. Set bunker_basement_drugs to a 50/50 spread between pharmacy drugs and soldier medical stuff instead of being weighted more towards misc pharma stuff.
4. Set bunker_basement_food to actually make use of mil_food_nodrugs.
5. Reworked bunker_basement_clothing to make more use of relevant itemgroups. Chance of getting NVGs and the like were shifted to the electronics spawn in bunker_basement_loot.
6. Adjusted the layout of the bunker surface, seating the bunker farther back so its stairs will actually line up with the basement level and moving the checkpoint rooms (now modeled more after the one at the helipad) up to the entrance. Also now gains some basic parking that connects to the gate, and potential for military zed spawns outside. Also had to basically rework the design so that it faces the same way as the basement, derp.
7. Updated overmap special and overmap terrain so that the basements can have rotations.
8. Defined a roof level for bunkers.
9. Redesigned the "cornucopia" variant of the bunker basement to be closer in design to the "actually livable" variant, having basic amenities that are actually accessible and a toned-down set of storage rooms locked behind card readers. Additionally comes with the bonus fun of turrets like the other variant that a card reader is additionally used to despawn. Loot is overall reduced but made more consistent, uses some of the extra itemgroups previously only used by the other variant, and no longer spawns mechs since that's now the primary reward of the military base.
10. Also adjusted spawns in the other bunker variant to be more consistent, general trend is the loot is a bit easier to crack open but less of the crazy stuff (aside from a more reliable source of bionics).
11. Axed the whole "variant of the autodoc bunker basement that's identical except for no corpse" in favor of turning it into a nested chunk spawn.
12. Adjusted how the blood splatters of the suicide event are set up so they can be set to have a chance to spawn in either bunker variant, as now both have an office.
13. Moved the mech nested mapgen ID to obsolete folder since it's now unused.
14. @Vollch pointed me to oter_id obsoletion files so I can correctly convert non-rotating bunker basements from old saves to the new version.
15. Toned down weight of the autodoc version a lil bit relative to standard bunker basements.

Describe alternatives you've considered

screm

Testing

1. Checked affected files for syntax and lint errors.
2. Load-tested with a save that already had one of the old-style bunkers generated. Confirmed the migration works and prevents the skippable error you'd ptherwise get with old saves.
3. Spawned in a couple new ones to eyeball the layouts.

Screenshots:

Surface:

Basement, variant one:

Basement, variant two:

Additional context

Checklist

[scarf005]

maybe we could make the floors use the floor used in labs later, as wooden floors might look a bit too... cozy

[chaosvolt]

maybe we could make the floors use the floor used in labs later, as wooden floors might look a bit too... cozy

Ah, so t_strconc_floor or t_metal_floor?

EDIT: Went with metal floor since it uses metal walls.

[scarf005]

LGTM

non-playtested review goes brrrrrr