update guide for end of online play

[lilyuwuu]

Do not merge until online services have shut down and it is confirmed that no 3DS update has been released!

• A9LH-to-B9S and Updating B9S: Remove reference to online play (should have done this long ago but I guess we forgor)
• FAQ: Remove reference to CFW working with online play (which no longer exists); keep message about bans in case people still ask
• Homepage, keyinfo, faq: swap out 3ds-11.17 (now gone, it's been almost a year) with 3ds-online
• Key-info: Adjust risks warning to remove reference to online play
• Region changing: Swap out reasoning for game updates
• Finalizing Setup: remove reference to Pretendo network dumps / SpotPass Archive

[lifehackerhansol]

Need to fix inclusion of 3ds-11.17.txt at top of faq.txt