Firestore as a source, events and projects

Added

• Firestore as a data source. Dashboards read from Firestore alongside the database types already supported.
• Events over an endpoint. Events can be posted to an endpoint that is reachable without a signed-in session, so a client can report them directly. The payload carries session information along with the event.
• Projects. Work can be grouped into projects, with a page that lists them.

Improved

• A quieter projects page. The projects list dropped its description text and the confirmation that appeared after copying.