October updates

[Xemdo]

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Problem/Feature

Forgot to add these in October

Description of Changes:

• Added is_featured to /mock/clips
• /mock/users/follows now returns 410 Gone
• Removed channel.follow v1
• Added 410 Gone responses to POST /eventsub/subscriptions on EventSub WebSocket server for removed events

Checklist

• My code follows the Contribution Guide
• I have self-reviewed the changes being requested
• I have made comments on pieces of code that may be difficult to understand for other editors
• I have updated the documentation (if applicable)

[Xemdo]

I'm dumb and forgot to actually remove /users/follows and also add /channel/followers but I'll do that tomorrow or something