Add gitlab integration tests.

We've moved hosting to a gitlab instance. Make use of the built-in
integration testing framework to verify commits.
3 jobs for gitlab-ci
Status Job ID Name Coverage
  Build
failed #2069
autotools

 
  Test
skipped #2070
check
skipped #2071
distcheck
 
Name Stage Failure
failed
autotools Build There has been a timeout failure or the job got stuck. Check your timeout limits or try again
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