Light support

[Shfty]

Lighting functionality varies game-by-game, so I don't want to standardize Qodot around a single existing implementation.

However, it would be much less useful to ignore light entities completely, given that there are creators deep into the Quake map ecosystem who've already done a lot of lighting work for maps they might want to use.

Current thoughts:

• Game-specific support can be implented through an EntityMapper subclass
• Having basic support for light params shared across all games would be good - position, intensity, etc
• Being able to spawn the lights outside the tree so they don't get nuked on reload would be a good optional pipeline for doing the broad strokes in TB, then tightening them up in Godot
• Could implement Godot-specific light definitions in the TB game profile that feed directly into the types and parameters available, so the option for full TB is available despite its lack of light rendering

Possible pipelines:

• Don't place any lights in the .map, do it all in Godot
• Use .map lights as a rough prepass, then manually tighten them up in Godot
• Use .map lights exclusively

[Shfty]

A basic light spawning system is now in place via the QodotBuildEntitySpawns build step. I did my best to match the Quake behavior of each parameter by eye where possible, but the systems are so different that making it completely accurate is an exercise left to the user.