CI: Updated script

- Determine dockertag based on branch name, to simplify structure
- Push to Hub instead of triggering a build (which is now behing a
paywall)
4 jobs for master in 2 minutes and 12 seconds (queued for 2 minutes and 22 seconds)
Name Stage Failure
failed
Build Build
--2021-12-14 11:28:11--  https://git.simply-life.net/packages/ubuntu/xenial/qommando-master.tar.bz2
Resolving git.simply-life.net (git.simply-life.net)... 94.130.102.147
Connecting to git.simply-life.net (git.simply-life.net)|94.130.102.147|:443...
connected.
ERROR: cannot verify git.simply-life.net's certificate, issued by 'CN=R3,O=Let\'s Encrypt,C=US':
Issued certificate has expired.
To connect to git.simply-life.net insecurely, use `--no-check-certificate'.
The command '/bin/sh -c wget "https://git.simply-life.net/packages/ubuntu/xenial/qommando-master.tar.bz2" -O /tmp/qommando-master.tar.bz2 && tar -jxvf /tmp/qommando-master.tar.bz2 && rm /tmp/qommando-master.tar.bz2' returned a non-zero code: 5
Cleaning up project directory and file based variables
ERROR: Job failed: exit code 5