[CR]Winning by closing the portal

[Coolthulhu]

As per #30

Progress:

• [X] Minimal endgame-finale mapgen
• [X] Victory function
• [X] Make mapgen generate the new endgame finales. Achieved it by replacing the lowest central lab finale on (0,0) overmap with endgame finale.
• [X] Have overmap gen always place the endgame lab.
• [X] Make sure player isn't spawned too close to endgame lab. Includes lab starts. Radius 1 around (0,0) is forbidden for spawns. That is, player will usually spawn on (2,0) and have to travel about 2 overmaps to find endgame.

Addressing issues from the issue:

I'd rather have it be the opposite, so the player spawns no closer than a set distance spawning within a set distance from (0,0) would limit the number of possible spawn points for the character, which is a problem for people who don't reset the world on dying or have multiple characters in the same world

Honestly, I thought something pretty much equivalent, just didn't communicate it clearly enough. The game naturally tries to place the characters close to (0,0), so adding a minimum distance isn't much different from adding a set (minimum which is equal to maximum) distance.

Maybe-planned, but not in this PR:

• More endgame than just a trivial switch flip
• Entering the portal and having a boss fight there (unlikely to ever happen due to technical limitations)
• Bringing the boss through the portal, for a local fight (actually doable)
• Endgame lab being visibly (and playably) endgame-y
• Endgame biome around the endgame lab

Dropped from this PR:

• Ensure consistent endgame lab length

[TrainTurningPoint]

@Coolthulhu Nice, thank you. I'll try to review it proper later today, but from a quick and uneducated glance an obvious problem is that the console can be destroyed. I'd imagine it would be pretty sad to have it happen, especially if some monster does it before player even reaches the room. Please make it indestructible if there's some easy solution for that. If not, that's something for a future issue.

[Coolthulhu]

I'll try to review it proper later today, but from a quick and uneducated glance an obvious problem is that the console can be destroyed.

I'll try creating an indestructible console type.

EDIT: Done'd

[TrainTurningPoint]

Ok, seems to be in working order. 3/3 attempts produced an endgame lab near (0,0). I expected my character to retire (commit suicide) automatically but it's fine if he doesn't. There's a problem with illiterate characters being unable to win, but I think it's outside of the scope of this PR.