Get rid of GeometryCollection

[m-mohr]

We are working towards v2 of the processes for vector cubes. I think this is a good chance to disallow and remove the already "not recommended" GeometryCollection from the processes.

Thoughts?

[soxofaan]

Getting rid of GeometryCollection as an allowed geometry type simplifies things for backend implementors, so that's good.
I have no idea if it is a valuable type for real use cases and end users.

Related: Open-EO/openeo-python-driver#71 (in VITO backend we handle a GeometryCollection as a feature collection, and we want to get rid of that inconsistency)

[m-mohr]

PR #395 proposes to remove GeometryCollection. It has been deprecated in 1.1.0 and as such is a good candidate for removal in 2.0.0.

[soxofaan]

PR #289 proposes to ...

I guess you meant PR #395 ?