Implement Ticket Created and New Comment notifications

[ChrisPenner]

• Merge Add Notification Topic Groups #87 first

Overview

Implements the notification triggers/subscriptions for creating tickets, and new comments on tickets & contributions.

Also sketches out the types for Ticket/Contribution status updates, but those aren't done yet; that'll be next

Implementation notes

• Adds database event topics for ticket created and ticket-comments and contribution-comments
• Adds those topics to the watch_project topic group
• Update the Share slack/discord feeds to track watch_project so they'll get these new updates.
• Implements the chat-app messages for the new topics
• Implements the hydrated data for the new topics (for hub and webhooks)
• Re-organizes data payloads to make adding more events a little easier

Test coverage

• Add the new notifications to existing notification transcripts