japanese/font-vlgothic: Update to 20230918 and take maintainership

Update MASTER_SITES, WWW and pkg-descr.
Lint with portclippy.
Refacor do-install.

Changelog (japanese):
https://raw.githubusercontent.com/daisukesuzuki/VLGothic/refs/tags/20230918/Changelog

PR: 277624
Approved by: hrs (maintainer timeout > 3 months)
Approved by: fluffy (mentor)