xrRender: optimizations and speedup (1/3)

Слиты xottab-duty запросил слияние feature/render_mt_calc в dev

Created by: vTurbine

This splits renderer into subsystems and adds parallel scene traversal for each of them: IMG_3199

Note: shadow casting lights are batched by 3 and re-use contexts from cascades calculation. In case if more contexts needed, one can increase R__NUM_AUX_CONTEXTS. Some of locks can be avoided if gameplay code will be untangled.

Next steps are:

  • parallel command lists recording (green events on the picture)
  • faster scene/lights occlusion + some opts.