updated LEAP archive signing key 0x1E34A1828E207901
Merge remote-tracking branch 'elijah/feature/known_hosts' into fix_develop
use default value for hiera lookup (#5118)
Merge branch 'fix_develop' into develop

This was needed so current develop plays nicely with latest leap_cli.
added a checkmk mode to the script `run_tests` (run with `run_tests --checkmk`. you can symlink `/srv/leap/bin/run_tests` script to anywhere if needed)
run_tests: added command line options --list-tests and --test (see --help)
Merge remote-tracking branch 'remotes/elijah/feature/checkmk' into 0.6