Max: Add missing workfile creator

[moonyuet]

Changelog Description

Add the missing workfile creator in 3dsMax.
Ported from Openpype: ynput/OpenPype#6203

Additional info

For some reason, get_subset_name function can't set the name with the correct variant, although there is variant.
It is using the old subset name workfileAsset.

Testing notes:

1. Launch Max via launcher
2. Load Scene
3. Open publisher
4. it should automatically create the workfile instance
5. you can notice the new container (which is hidden and greyed out) named accordingly
6. Publish workfile
7. It should be successfully published.

[BigRoy]

Didn't test it (don't use Max) but overall code changes look okay on first sight.

[LiborBatek]

All working as expected...

tested in max 2024