add delete_live + check_diskspace to bootstrax. Switch to rundb. Misc changes.

Created by: jorana

These are several changes made to bootstrax. Several features were added that were deemed usefull after/during the ceph stress test (https://xe1t-wiki.lngs.infn.it/doku.php?id=xenon:xenonnt:dsg:daq:ceph_stress_test).