Axes TS gateway

[AffectedArc07]

Note

This PR already has unanimous approval from the design team. Its happening.

What Does This PR Do

Removes the terrorspider gateway as parts of the work of converting gateway missions to space ruins.

The reasons this one is being axed instead of converted are multiple, but most notably:

• This gateway has a very linear design, which doesnt work for space ruins because you can attack them from all angles
• A lot of the stuff for this gateway relies on forced z-level checks, which dont work for ruins (see players being bitten then gibbed as they swap z-level, the wireless e-guns that use forced Z-level checks, etc etc)
• The general fit of the gateway just doesnt fit being a space ruin well. Its too large, easily cheeseable, and tends to not be super fulfilling

A TS themed ruin will return some day, but I dont know when. Probably after TS get a bit of a refactor to make the AI stuff a bit more sane (They really need a /ai subtype that handles the stuff for them, instead of tons of vars to forbid player possession and similar)

Why It's Good For The Game

Gateway must be purged

Testing

The code compiles. Might be worth doing a TM to make sure regular terrors arent busted, but I doubt they will be.

Changelog

:cl: AffectedArc07 del: Removed TS gateway /:cl: