.gitlab-ci.yml: stage 'test_germlines' for 'feature-g' branches

See #3036.
3 jobs for dev in 27 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test Tools
passed #63032
test_tools

00:00:04

 
  Test Quality
passed #63033
web
code_quality

00:00:12

 
  Test Unit
passed #63034
web
test_browser_unit

00:00:10