I posed this MR into the box-facet-coupling branch so that the diff is easier to read. If we wait for !1492 (merged), which itself has to wait for !1431 (merged), then we can merge this into master at one point.
deprecate old interfaces
change all tests where cm now receives grid variables
create an issue to remove the deprecated interfaces in all facet coupling managers and the poroelasticcouplingmanager until version 3.2 release(edit Timo: don't need an issue for that)
update reference to
test_md_facet_tracer_box(velocity is included now, which tests the MD vel output)
Put a note in the changelog that scvfs now have to implement