Make Bioformats isRGB method available in the API

[dominikl]

See https://forum.image.sc/t/isrgb-attribute-in-omero-image-reader/96992 .

I openend a few draft PRs, but I'm not sure if I miss something or how I could test them all together.
Is there a simpler way than local building with publishToMavenLocal and adjust all versions manually, @jburel ?

• Add isRGB methods omero-romio#43
• Add isRGB method #182
• Add isRGB method omero-blitz#153
• Add isRGB method omero-common#46
• Add isRGB method omero-gateway-java#94

(Of course the builds all fail because they all depend on eachother.)