Add a docs feedback widget to allow upvoting and downvoting pages.
Votes (completely anonymized, barely more than a counter) go to a database in the main supabase-com project. If the user has accepted telemetry, the votes also go to Logflare with a bit more info. Post-vote, logged-in users can leave a comment, which goes to the `platform/feedback/send` endpoint. There is a warning in the feedback modal that the feedback is not anonymous.
