Make AI Model Training work with tasks

[daniel-wer]

Detailed Description

As far as I can see two things are missing:

• Allow to specify task IDs instead of annotation IDs as the training data source. To do this I think it would be easiest to look up the (or are there multiple?) annotation ID for a specific task ID and continue to use that. This way, no changes in the worker should be needed. (@fm3 Could you comment on whether that's possible?)
• Take into account task bounding boxes and not only user bounding boxes

Context

• Specific to long-running jobs (set jobsEnabled=true in application.conf)

Training data for model trainings is often created using tasks. It should be possible to start a training from these.

[fm3]

Sounds good! Yes, there may be multiple annotation ids per task. We should also decide if only “finished” instances should be used, or also “active” ones.