feat: Conference / Event templates & blocks features

I'm interested in creating ticketed event sites but I don't see an templates designed to support events.
- Keynote, Electives, Register, Agenda, Sponsors etc

• A block that I need to support for such a site is a count down timer (showing date, hours, minutes, seconds to start time) that we'd configure with the event start date and time.

• Adding conditional blocks that show/hide based on dates would also assist for this kind of site.

Further inspiration
- https://themeforest.net/search/events