Factor out dune check module version out of find_dune_package

The intent here is be able to check dune module version outside of the find function in CMake. See !1249 (comment 132296) for more details on the intended use case.

requested review from @simon.praetorius

mentioned in merge request !1249 (merged)

Looks good.

approved this merge request

merged

mentioned in commit fbf2b010