website: Overhaul ports visibility
header: move ports to Get FreeBSD
footer: add ports, remove 44bsd docs archive. It is still in docs/
where/: remove ports, and remove it from the sidemenu
Event: Berlin Hackathon 202609
Reviewed by: wosch
Suggested by: wosch, michaelo
Differential Revision: https://reviews.freebsd.org/D59442