TVPaint store context to workfile metadata (764)

[iLLiCiTiT]

Issue

It is possible to have opened multiple workfiles at the same time from different contexts. Which is not an issue for most of avalon workflow but is issue for publishing.

Changes

• each workfile contain metadata with "project", "asset" and "task" to keep context in which were workfiles created.
• these metadata are loaded in first TVPaint's collector and current context is modified by them
  • if workfile does not contain these metadata current context from api.Session is used
• added validator for comparing project name (it is not allowed to publish in different project)

Possible issues

• manually copy-pasted workfile (out of workfile tool) may contain metadata from different context
  • this can be fixed with resave
• workfile change is not "Super Responsive" TVPaint won't change workfile context at the moment of tab change (it is required to click somwhere in gui).

🏴	this depends on
avalon-core	ynput/avalon-core#233

Resolves #764