This adds the capability for the user to attach a reason when removing
or destroying a rule. The message will both be logged in netcontrol.log
and forwarded to the responsible plugins.
Addresses BIT-1655
This has no user-facing changes. It makes the internal handling of rules
much easier (no crazy duplicate rules in case our rules are added to
several backends).
It also fixes several open ends and small bugs in the process.
Netcontrol log now includes more information; before that, it had not
quite caught up to the new capabilities (like flow modifying and
redirection, as well as mac addresses).
Furthermore, this fixes a number of bugs with cluster mode (like
duplicate events), test failures due to updates in Bro, etc.
