(legacy style code) work on https://github.com/opnsense/core/issues/405 packet normalisation, needed for further restructure and cleanup of filter code.

Spotted by: @fabianfrz

Also remove the captive portal RRD graph removal.  We really need
to improve the GUI in order to solve the issue of stale RRD files
gracefully.

PR: https://forum.opnsense.org/index.php?topic=3082.0

... Ad already annotated a few spots, the whole thing is beyond
repair and I dread extending it to PPP and others which has been
asked for a few times now.  We will have to find another way.

To paraphrase Star Trek: He's dead, Jim.

The upside is that the cron config items are flushed by default
now, later we can remove this as we don't care what is in that
unused config section anyway.

PR: https://forum.opnsense.org/index.php?topic=3105.0

for example, return all active non virtual interfaces:

$interfaces = legacy_config_get_interfaces(array("virtual" => false, "enable" => true));

"reserved" names in interfaces leads to converting arrays to arrays in arrays, not easy to solve without the need to change a lot of the legacy code in same run.

whitespace cleanup

PR: https://forum.opnsense.org/index.php?topic=3092.0