Add ability to control pam_limits via new module 'limits'
1) 'Values' configures limit settings to be persisted.
2) Previous DivingBell controlled limits those were set
but now are gone are cleared.
3) Previous values of newly set limits are backed up
4) New limit is applied via adding a separate conf file
5) The Doc is updated with appropriate details.
6) Dev env with Vagrant
7) Increase number of expected DaemonSets in 020-test
8) Demo: https://asciinema.org/a/209619