[fix][heavyoil] set injection area back to what it was in 2.12 as well as van...

This MR is necessary as with the change to dumux 3.0 several bugs where introduces. The injection area was changed (to vertex not cell center) which lead to unphysical behaviour for the cyclic tests. Additionally the Van genuchten parameters are now changed back to the values from 2.12.

The unphysical behaviour of the cyclic tests was not observed by the tests, as the tests stopped before the injection. To avoid that in the future, we now start with an injection period in the cyclic tests so that we actually test something. The tests all do not have a reference solution. Still we now can at least check that the tests at least run during injection, which they did not with the previous version.

This fixes #7 (closed)