Add new menulibre port to xfce4-goodies metaport

[madpilot]

Summary

I recently added the x11/menulibre to the ports collection.

XFCE has bindings (for example in xfce4-whiskermenu paanel plugin)
to call it to modify the appplication menu layout.

I also noticed many linux distributionss do bundle it with their
xfce4 insstallations, and since it is actually a useful thing to
have I'd like to add it to the xfce4-goodies metaport.

Test Plan

Not much to test, being just a metaport.

[madpilot]

Committed in ports r472679