Blender Git Loki

GPU: Sizecheck for push constants buffer.

According to the specs platforms should at least support push constants
of 128 bytes. As there are known platforms that have set this as their
maximum (Mesa for example) we should use this as the maximum as well.

DrawManager: Add push constants command.

GPU: Binding uniformbuffer as push constant.

GPU: Added push constants to shader interface

Cleanup: Renamed converter to patcher.

Refactored GLSL patching for future extension.

Every patch would be its own class this would keep the data and logic contained.
When a source is unchained during patching it would reuse the original source.

[WIP] GPU: Push Constants.

See T89553 for more details.