Maya: Vray scene publishing

[antirotor]

Feature

This PR adds ability to work with vrayscene type with more control. It inherits basic principles from rendering family. So when you create vray scene instance, it monitors render layers and create set under instance for each of them, tracking changes. If you leave that set empty, it will export whole scene under that render layer context to vrayscene. However if you add objects/sets there, it will export only those under render layer context.

This is currently publishing only on local computer (not utilizing render farm) and it doesn't support multi-frame sequences of vray files.

Changes in renderning publishing

This PR is also introducing changes in current rendering publishing system. It drops LAYER_ prefix in names of sets created under rendering instance. Instead it prefix them with Maya namespaces. By default new namespace is determined by name of render instance with added underscore before it - renderingDefault and render layer FOO will result in _renderingDefault:FOO named set under rendering instance. If _renderingDefault exists and is not empty, it will try to create next available name appending increasing number at the end, so next available namespace would be _renderingDefault1.

This change mitigate chance of name conflicts in scene as Maya doesn't allow two objects under one namespace to share name.

🎫 Freshdesk: 67
📖 Documentation: ynput/pypeclub.github.io#34

[mkolar]

missing 3.x PR