`apply_polygon`: rename `polygons` parameter to `geometries`

[soxofaan]

apply_polygons has a polygons argument:

openeo-processes/proposals/apply_polygon.json

Lines 19 to 20 in 965bbae

	"name": "polygons",
	"description": "A vector data cube containing at least one polygon. The provided vector data can be one of the following:\n\n* A `Polygon` or `MultiPolygon` geometry,\n* a `Feature` with a `Polygon` or `MultiPolygon` geometry, or\n* a `FeatureCollection` containing at least one `Feature` with `Polygon` or `MultiPolygon` geometries.\n* Empty geometries are ignored.",

This is not in line with comparable processes that use geometries for the same concept, like aggregate_spatial, filter_spatial, filter_vector, vector_buffer. Note that mask_polygon also doesn't use polygons.

It also appears to be confusing users about how MultiPolygons are supported

[m-mohr]

Fine for me, would be breaking though. So is it also fine for VITO to have a breaking change here?

[soxofaan]

with Open-EO/openeo-python-driver@15b72a7 VITO implementation will support both geometries (preferred) and polygons (legacy)

[m-mohr]

Would you mind creating a PR for this in openeo-processes? @soxofaan