Refactor: local and farm rendering

[antirotor]

Is there an existing issue for this?

• I have searched the existing issues and added correct labels.

Please describe the feature you have in mind and explain what the current shortcomings are?

Local and farm rendering is trying to use the same workflow, but with very different logic. Local rendering is expecting files to be already created before running publish, on the other hand farm rendering is "just" creating farm job - it is not processing existing files nor it is creating them.

Right now we are creating new instances from existing instance in collectors, deleting old ones but since it is splittled between different collectors that can run in different order, it is very fragile.

Suggested implementation?

We need to refactor CollectRenderInstances (collect_render_instances) and CollectUnrealRemoteRender (collect_farm_render) where new instances are created so it is more under control and the data is shared as much as possible. In CollectUnrealRemoteRender, there is a use of UnrealRenderInstance() to create render instance - but that one is used for different purpose than in CollectRenderInstances.....

Describe alternatives you've considered:

No response

[antirotor]

Some of it was partly done here #165 but more work needst to be done.