Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r264840: Implement GEOM based media device classification.

MFC revisions 255908, 255925, and 255925:

SVN r255908:
Fix a bug in HTTP checking/fetching. Add Main Site to HTTP menu. Add new
example script browse_packages_http.sh and move existing example script
browse_packages.sh -> browse_packages_ftp.sh

SVN r255925:
Remove the is (Iceland) mirror per mail from the admins.

SVN r255925:
Remove ftp5.se.f.o, as per request to -hubs@

Fix a bug in HTTP checking/fetching.
Fix a bug in HTTP checking/fetching. Add Main Site to HTTP menu. Add new
example script browse_packages_http.sh and move existing example script
browse_packages.sh -> browse_packages_ftp.sh

Reviewed by: gjb, brd
Approved by: re (gjb), clusteradm (brd)
MFC after: 3 days