LD3_Washout a3

- Dramatically reworked mid to feature two "bunkers", and pits connecting mid to an expanded big health underpass
- Flank fields dramatically expanded
- Bulletproof glass on base-facing windows at B and D.
- [EXPERIMENTAL] removed the front stairwell into B and D to give more power to bridge route when extended.
- More los-blocking geometry.
- Some prop revisions and early displacement work

I caught covid halfway through this iteration and had a soft jam deadline to wrap it up by, so there are some changes I'm not 100% on.

A small update from the previous (unversioned) build with a few small changes
- Spawn Door gaps closed
- Ramp removed from battlements
- textures on cliffs