We mount now a directory to /opt/slurm that contains executables of
slurm version 17.11.13.  This version is again compatible with the version
that runs on head.cep4.

Cherry picked from commit https://svn.astron.nl/LOFAR/branches/RT-Task11326@38649.

Reinoud recommended for proxy/firewall/easier-to-maintain reasons that
the static files should be moved from /static/ to /triggers/static/.
  # Please enter the commit message for your changes. Lines starting

Also added a directory "edit_these_files" that shall contain files that the
user must edit before building the Docker image.
Added README.md that describes what the user should do the receive proper
user credentials to put in the mom.ini file.

Task #10983: Propagate /etc/{group,passwd} from the host instead of modifying the one in the container, removing a few quirks

Task #10975: Docker outputproc: add setcap for TBB_Writer (its commissioning has started by Joeri's group)

Fix merge conflict on momqueryservice.py. Moved on trunk, but changed on this branch.
Solve by replacing the moved file with the changed file (thus, move the changed file over the moved file).
Careful checking of (JD's) changes shows this is correct; the changes are preserved.
Other moved files did not cause conflicts, since they were not changed.