Activity Log: I want to know what's happening in my local network

[bfollington]

We recently introduced the activity table which tracks when:

• you follow a user
• you unfollow a user
• you update a note
• a peer publishes new changes
• a peer linked to your note

We can extend this to also track when peers follow a new user if we index peers-of-peers.

Using this activity log we can implement a reverse chronological “feed”.

[bfollington]

Updated after a round of feedback from @gordonbrander