Merge branch 'feature/petsc_cmake' into 'master'

Feature/petsc cmake

See merge request !80
6 jobs for master in 44 minutes and 28 seconds (queued for 38 minutes and 1 second)
Status Job ID Name Coverage
  Test
passed #11935
dune-2.6 debian-10 gcc-8-17

00:13:51

passed #11936
dune-2.6 debian-9 gcc-6-14

00:12:26

passed #11937
dune-2.6 ubuntu-18.04 clang-6-17

00:11:33

passed #11938
dune-git debian-10 gcc-8-17

00:16:12

passed #11939
dune-git debian-9 gcc-6-14

00:13:45

passed #11940
dune-git ubuntu-18.04 clang-6-17

00:11:39