[FEATURE] Support for File Output compositing node

[rabits]

Is your feature request related to a problem? Please describe.

That will be great to store the file output node results along with the common compose result - those nodes used to save intermediate compose results, that could be used later in the pipeline.

reported by: @heizermeister

Describe the solution you'd like

I think it's possible to add status.result.compose_additional field where the additional files could be stored. Basically it needs to tell where to store the file and what is the blob id is. Of course the additional result should be detected and stored in the cache.

Additional context

For now such results are ignored and only the compose result is stored.

[rabits]

Hmmm, so it's quite hard to figure out the actual file path... That's needed to support the cross-platform rendering and solve the absolute path to properly store the output files on the server. Probably it's possible to store them in the temp files, but that will be hard to properly store the results on the client...

[rabits]

After the Halloween I got an idea - each file output/input contains the path, so it's possible to hash it and use this hash to store the file on the Agent and make the whole pipeline consistent.

Unfortunately this doesn't solve the issue with storing the files on the Client side...

[rabits]

Nope, that will not work, because if we specify a directory - it will be stored as dir/Image0030.png...