Support ROI output

[TorecLuik]

Probably people want to upload ROI objects (as results from a workflow) to OMERO, instead of just label images. Or perhaps both.

We note the limitations of OMERO (web) in handling ROIs, but we could add the uploading option as a feature.

Anyone has a workflow that outputs standardized ROI objects? What types of data do we have to handle as ROI objects? Should we extract ROIs from a label image?

More info/thoughts needed

[CellularImagingCF]

Wendt has a OMERO script to postprocess/convert label images into ROIs. Could be good enough for this use-case? https://forum.image.sc/t/omero-script-to-convert-grey-value-label-images-to-omero-rois/93923