Studio lights had gone over several iterations during 2.80. Some
unused options where still in the code, but not used.
This PR cleans up the studio lights to options that are still in use.
Removing:
- Spherical Harmonics: It was used by workbench, but was replaced
by regular OpenGL lights
- Irradiance textures: Was used by an old eevee world light evaluation
- Cached data files.
Pull Request: https://projects.blender.org/blender/blender/pulls/116186
a52a362527