Additional Shadow Programs

[Luracasmus]

Is your feature request related to a problem? Please describe. Currently, Iris only offers one shadow program for all types of shadow geometry, while non-shadow geometry is split into many different gbuffers programs

Describe the solution you'd like Similar to the existing Iris Additional Programs, add support for translucent/water and cutout shadow programs, and possibly even separate shadow programs for terrain, entities, block entities, etc.

Describe alternatives you've considered Use mc_Entity and/or renderStage in the shadow program to separate different types of geometry at runtime