Allow configureable update rate for infotex

Needs some work, ideally, ill put some lua callins to allow adjusting the rate at which varios infotextures are updated. The engine source seems to use fixed update steps, which are especially slow for large maps of 24x24.

The ones that need an update

1. LOS texture
2. Passability/buildability texture

No files or tests are named. Start by locating the engine code that updates infotextures, then trace the LOS and passability/buildability update steps and the existing Lua integration points. Done means both texture update rates can be adjusted and the behavior is verified on large maps.

Written by the indexing model from the issue text.