[Feature: 1262] userspace/wrsw_rtud: support of removing rtu entries

wrsw_rtud:
--remove "force" param for minipc call rtudexp_clear_entries
--pass port mask instead of port number for minipc call rtudexp_add_entry

rtu_stat:
--add a possibility to add RTU rules for a given port mask
--add a possibility to remove single RTU rule
--add a possibility to remove RTU rule for a given port mask
--add verifying of MAC address
--improve help

Signed-off-by: Adam Wujek <adam.wujek@cern.ch>