make the unfollow button go clicky clicky

[iandioch]

Closes #318.

1. Adds a "delete follow" bit to the database service.

• + tests

2. Adds unfollow endpoint to follows service

• + test

3. Adds skinny endpoint to forward unfollows to follows service
4. Adds logic in frontend to send unfollow request when unfollow button is clicked.
5. Removes the alert boxes when you click the follow or unfollow button successfully (which makes it feel 100x smoother and nicer, and makes errors less scary)

[SailSlick]

seems grand

[iandioch]

Thanks for the review fren