Merge branch 'mapStM' into 'master'

Add mapStM, a combination of mapM and mapSt

See merge request !237
2 jobs from master in 3 minutes and 13 seconds (queued for 6 seconds)
Status Job ID Name Coverage
  Test
passed #39043
test-nightly

00:01:19

passed #39044
test-stable

00:01:53