Full CMake refactor

Changes

No need to have some strange compilation strategies:

• The root CMakeLists.txt allows compilation of all utilities (mainly finish #85 (closed)).
• CMake determines if it have the necessary libraries to build malia and malia_rgb.
• Additional rule blender-bridge allows creating the zip file for Blender plugin (fixes #176 (closed)).
• Repository cleaning (see the legacy folder for stuff that we do not need now).
• Updated documentation to reflect the new method for compiling malia and malia_rgb.
• All references to included files from mrf_core or mrf_optix use the standard chevron methods. There is a single exception on a .inl which shall be fixed in the future. STL libraries come after the mrf includes.
• Fixed some missing includes.
• CI jobs compile
  • blender_mrf.zip for Blender plugin
  • For Windows, a 7z package
  • For Linux, two AppImage (malia and malia_rgb).
• Simplification of the snap creation for Linux distributions.

Future work

Further improvements can be done here and there but, the main structure is here and shall be much easier to work with.

Extra note

Could not properly squash my commits in an intelligible way due to a merge from master an my poor git abilities. Then, I think we can squash the whole thing when merging to master.