Fix NMap timeout when started from GUI

[PhilZ-cwm6]

Redmine: https://redmine.pfsense.org/issues/12963

NMap package cannot actually run from gui because of nginx timeout This patch adds the following features:

• run nmap in background and output results to /root/nmap.result filr
• do not start a new nmap session from gui until last one is completed
• add a results tab to get the last log output from nmap
• show the time of last nmap scan completion (start time is displayed by actual command output)

[jim-p]

Looking at https://nmap.org they seem to prefer Nmap or nmap, I don't see anywhere they capitalize it as NMap. We should standardize around their preferred format, so using Nmap is best. There are existing references in both styles in the package but this PR adds a lot more, so it's a good time to correct it and make them consistent.

[PhilZ-cwm6]

Looks OK now, though it needs a version bump:

As a part of this pull request, you must increase PORTVERSION or add a PORTREVISION line in the package Makefile. Without this version increase, the package will not be rebuilt to include the new change.

See https://docs.netgate.com/pfsense/en/latest/references/developer-style-guide.html#ports-packages-specific-rules

It would also be very helpful if you could squash the commits into a single entry: https://stackoverflow.com/a/5668050

Thank you for your directions I squashed all commits in a single one + PORTREVISION increase Is it ok as it is or should I push a new pull request from the squashed branch ?