Arch: adapt materials to new Materials path scheme

[furgo16]

Fixes #13821 by adapting the old material paths to the new scheme:

1. Update the materials filesystem path when reading them
2. Materials can now be in subfolders: traverse directories to read all materials

I'm aware of #13821 (comment). I've addressed this as a quicker way to get back the Materials function before #13783 gets merged, which might take longer. The intention is certainly not to step on anyone's toes, so if this is already being worked on, or can be fixed in a better way, feel free to close this PR.

[davesrocketshop]

It should only be necessary to change the path. The other changes will break other workbenches.

[furgo16]

@davesrocketshop thanks again for doing the review. I believe the new changes address your review comments. Let me know if that looks ok.

[davesrocketshop]

@davesrocketshop thanks again for doing the review. I believe the new changes address your review comments. Let me know if that looks ok.

It does. You might also want to look at materialtools.cardutils.get_material_resources() that builds the path for you including user materials, custom folders, and any added by add on workbenches. The need goes away though as the module transitions to the new materials system so that may not be necessary immediately.

[furgo16]

Thanks. I'll look into get_material_resources() for the next iteration. I had wondered if there was a dedicated function, but I had not found it. I'll look at the code examples I see in the cardutils.py comments in more detail, then.

[yorikvanhavre]

Thanks @furgo16 ! This can go already I guess. I'll rebase #13783 on it