(fwRenderOgre): clean the media folder

What does this MR do?

Sorts glsl, metarial and compostior.

How to test it?

⚠ Cleans fwRenderOgre and material folders of your build folder.

Launch OgreViewer and test volume settings, compositors parameters and meshes render settings.

Associated Issues/Merge Requests

• Issues
  • See #456 (closed)