Revert "[cmake] use GridUtils to define GRIDTYPE and GRIDDIM"

This reverts commit e90dfa4e46491e1c909995c7dc74bf5f0c68b9a1.

Setting the GRIDTYPE with FORCE does not make any sense of course
(since it overrides any manual change immediately).
[cmake] apply parts of e90dfa4

The problems remain however how to enable alugrid in the tests...