We currently stick to Snakemake.

Allows for e.g. utils only tests with:

```
-DOGS_BUILD_UTILS=ON -DOGS_BUILD_CLI=OFF
```

EXECUTABLE argument is now required on AddTest().

Test runs on envinf1.

Both tests write to and read from the same files. Now they run after
another. Should fix sporadic CI errors.

Add switch -a to create additional points in the geometry.

-s, -m, -i args are already in use.

Also fixed ctest dependency and enabled ogs2metis test for mac.

WORKING_DIRECTORY.

Adapt utils tests to new working directory.

Metis converted input prepared with
partmesh -i cube_1x1x1_hex_8.vtu --ogs2metis
mpmetis -gtype=nodal cube_1x1x1_hex_8.mesh 2