create GLSL shader annotation and analysis library

[ScanMountGoat]

This should use the updated code created for xc3_lib once it's more finalized due to better performance and reliability compared to the implementation in this repository.

[ScanMountGoat]

The code from here can be used as a git dependency or converted into a library eventually. This will replace the glsl-dependencies and annotation logic as well as code analysis like detecting premultiplied alpha.
https://github.com/ScanMountGoat/xc3_lib/tree/main/xc3_shader