x11-wm/pekwm: Update 0.3.0 => 0.4.3

Changelog:
https://www.pekwm.se/pekwm/file?name=NEWS.md&ci=release-0.4.3

Port changes:

• Adapt MASTER_SITES since upstream moved to GitHub.
• Replace .if conditional with PANGO_USE instead.
• Add pekwm.desktop file for better reference in various DM

PR: 293371
Reported by: Vincent <vincent.delft@gmail.com> (author)
Approved by: Natacha Porté <natbsd@instinctive.eu> (maintainer)
Approved by: osa (mentor), vvd (co-mentor)