Merge branch 'ci/ralf/ci' into 'master'

install CI and update build system

See merge request !1
2 jobs for master in 12 minutes and 34 seconds (queued for 13 minutes and 42 seconds)
Status Job ID Name Coverage
  Build
passed #10595
fp
build-coq.8.6.1

00:12:34

passed #10594
fp
build-coq.8.7.2

00:11:48