www/kanboard: Update 1.2.46 => 1.2.47, take maintainership

Changelog:
https://github.com/kanboard/kanboard/releases/tag/v1.2.47

Improve port:

• Fix permissions for %%WWWDIR%%/data directory.
• Fix warnings from portclippy.
• Sort plist.

PR: 288811
Co-authored-by: Vladimir Druzenko <vvd@FreeBSD.org>