Blender Git Loki

Fix T80191: GPencil - Improve Mesh conversion

There were some problems when converted several objects at the same time, especially with the material conversion. The problems were more visible when bake an animation with several objects at the same time.

* Now the layer name include the object name.
* Reorganize how the materials are generated including object name.
* Fix color not converted to sRGB.
* Avoid triangles when generate the stroke. This fix a draw manager issue and also add more geometry to use later.
* Code cleanup.