One resource is used for shader version 1.10 and one for version 1.40.
The ideas behind this change is to remove the locating of the shader
sources and also to fix that user provided shaders could be loaded
instead of the original ones (possible attack vector on Wayland).
To simplify the ShaderManager provides a new method call to load the
shader from the resource. This means the effects don't need to
duplicate the check for the shader version any more and also don't
need to duplicate the file reading functionality.
REVIEW: 126905
Martin Gräßlin