x11/plank: Moved from x11-wm/plank, updated to 0.11.89 and request port maintainership.

[daniel_shafer.cc]

Summary

x11/plank: Moved from x11-wm/plank, updated to 0.11.89 and request port maintainership.

* Various adjustments/fixes and preparations for 0.12.0
* Port moved as incorrectly labeled under windows manager but is an independent dock application.

PR Created: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=241302

Test Plan

portlint: looks okay.
poudriere: (testport, 12Samd64, good)

[daniel_shafer.cc]

Fixed a typo

[tcberner]

Looks good to me.