Merge branch 'feature/interpolation' into 'master'

Feature/interpolation

See merge request !5
6 jobs for master in 10 minutes and 11 seconds (queued for 7 seconds)
latest
Status Job ID Name Coverage
  Test
passed #7505
dune-2.6 clang-6-17

00:05:16

passed #7503
dune-2.6 gcc-6-14

00:04:31

passed #7504
dune-2.6 gcc-8-17

00:06:08

passed #7508
dune-git clang-6-17

00:04:52

passed #7506
dune-git gcc-7-14

00:06:14

passed #7507
dune-git gcc-8-17

00:05:15