net-mgmt/etherape: Update 0.9.20 => 0.9.21, take maintainership

Changelog:

• GooCanvas was unsupported and getting really old, replaced by GtkDrawingArea.
• --final-export is primarily meant to be used from other tools as a way to get statistics data from a replay. As such, --final-export exits automatically after the file replay ends and the dump is written.
• Compatibility Warnings:
  • removed GooCanvas dependency, drawing now done with plain Gtk.
  • new behavior for --final-export: exit after saving the XML dump.
• Changes summary:
  • Updated german translation, thanks to Christoph Brinkhaus.
  • Fix for german translation, thanks to Ronald W. Henderson.
  • Fix for gcc 15, thanks to Petr Gajdos.
  • Assorted refactorings and small modernizations, including autotools.

Improve port:

• Replace PORTVERSION with DISTVERSION.
• Remove unused dependencies.
• Fix detection and build using libpcap from the base.
• Remove unnecessary GNU_CONFIGURE_MANPREFIX.
• Add option NLS.
• Make the DOCS option handle help files.
• Refresh patches.
• Sort pkg-plist.

PR: 294190
Sponsored by: UNIS Labs
MFH: 2026Q1
Co-authored-by: Vladimir Druzenko <vvd@FreeBSD.org>