manager: Implement whitelistfirewall

whitelistfirewall manager is locking down partition access as configured in
partition's .slapos-whitelist-firewall file by using firewalld configuration.

The md5sum of last generated partition whitelist file is used to take
decision if given rule shall be updated.

The manager supports partition setup and destruction.

Note: User id is used with netfilter owner module, as currently the sourcing
      address is not enforced to be per partition.