Fix IPv6 Outbound NAT

Rules using "Interface Address" as the NAT target IP did not select the
IPv6 address when generating the rule

Firefox and Safari are unaffected.  No harm done in deleting a
pointer to a non-existing source map.  Oh my.

Inspired by: @adschellevis

maybe, one day, we should refactor some of the JS code... but for now this will do the trick

(reporting/settings) option to flush all local netflow data. closes https://github.com/opnsense/core/issues/983

(rrd) add configd "systemhealth flush" command, add flush single report. closes https://github.com/opnsense/core/issues/984

Bravely assisted by: @ShaRose

(interface groups) trigger missing to notify changed interface administration, closes https://github.com/opnsense/core/issues/1064

Language correction: more generic expression

PR: https://forum.opnsense.org/index.php?topic=1668

(fw, alias) refactor update_alias_names_upon_change to support nested alias renaming, closes https://github.com/opnsense/core/issues/1028