Add Gitlab CI config file

6 jobs for master in 15 minutes and 18 seconds (queued for 3 seconds)
latest
Status Job ID Name Coverage
  Build
passed #226543
build

00:03:28

 
  Test
passed #226546
autopkgtest

00:03:39

passed #226547
blhc

00:01:56

passed #226545
lintian

00:02:04

passed #226548
piuparts

00:05:38

passed #226544
reprotest

00:03:22