appletalk: move the protocol out of tree

appletalk: move the protocol out of tree

AppleTalk has been removed in MacOS X 10.6 (Snow Leopard), in 2009,
according to Wikipedia. We recently got a burst of AI generated
fixes to this protocol which nobody is reviewing.

Let AppleTalk follow AX.25 and hamradio out of the Linux tree.
We we will maintain the code at: github.com/linux-netdev/mod-orphan
for anyone interested in playing with it.

Retain the uAPI for now. No strong reason, simply because I suspect
keeping it will be less controversial.

Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Link: https://patch.msgid.link/20260615222935.947233-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>