Allow configuration of acquisition stage per workflow step

[matthias-ronge]

The acquisition stage in the rule set determines which metadata fields are visible and whether they can be edited or not. At the moment, this is hard-coded create for the creation of processes and edit when using the metadata editor. It should be configurable for each workflow step.

This work needs three parts:

• Provide list of acquisition stages to workflow editor #4516
• Provide to store acquisitionStage per task #4517
• Extend the workflow editor to select an acquisition stage per task #4518