Mirror `daq-release` at CERN gitlab, and run CI tests on NP04 nodes

[dingp]

During Tuesday's SW Coord meeting, we agreed that for security reasons, it's better to use CERN gitlab for CI tests on NP04 nodes.

These tests can include:

1. Daily validation of nightly releases, which also serves the purpose of populating squid server's cache with latest files from cvmfs;
2. Routine validation of a new frozen release, including setting up work area, build and run, as well as running dbt-setup-release;
3. Routine integration tests which can be run in batch mode.

[dingp]

Assigned to to future release 3.1.0.

For the time being, I will set up cron jobs at NP04 and scripts for building the frozen release, running basic integration tests etc.

[dingp]

Change the target release to 3.2 as we did not have a chance to work on this yet. It may be deferred to post 3.2 though.