RubyKaigi 2023: Prep

[sorah]

### Tasks
- [ ] https://github.com/ruby-no-kai/takeout-app/issues/66
- [x] presentations, speakers
- [x] sponsors
- [x] promo texts
- [ ] https://github.com/ruby-no-kai/takeout-app/issues/68
- [ ] https://github.com/ruby-no-kai/takeout-app/issues/67
- [x] flag speaker/committer

[sorah]

S3 bucket is empty as we've moved to usw2

bundle exec hako oneshot takeout-batch.jsonnet bundle exec rake takeout:sync_conference_data