[blender_ls3_doc] Add documentation for blender_ls3
[blender_ls3_doc] Elaborate on mesh optimization
[blender_ls3(_doc)] Add feature to preview variants in 3D view
[blender_ls3] Respect Blender's "sharp edges" feature
[blender_ls3] Add batch export feature
[doc] Move documentation into subdirectory
Merge documentation from blender_ls3_doc into own subdirectory