Merge branch 'bfield' into 'master'

Adapt ViewField to be able to plot magnetic fields.

See merge request !246
5 jobs for master in 6 minutes and 11 seconds (queued for 3 seconds)
Status Name Job ID Coverage
  Build
passed build-centos7 #17099373

00:03:25

passed build-centos7-view97 #17099374

00:06:11

passed build-fedora32 #17099376

00:03:35

passed build-fedora33 #17099377

00:03:37

passed build-ubuntu #17099375

00:04:33