net-firewall/shorewall*: v4.5.19 version bump

* ebuilds updated
 - ebuilds do now support upstream's beta and RC versions
 - Dependencies revised
 - ebuilds unified
 - ebuilds will now check for suitable kernel configuration

* shorewallrc file updated

* Init scripts updated
 - Description text added
 - Help text added
 - Init scripts unified
 - "-f" parameter usage removed
 - Every /sbin/shorewall* call output will now be redirected to /dev/null
   if applicable
 - Extra command "refresh" and "check" removed from shorewall6?-lite,
   because these commands are not supported by shorewall6?-lite