Remove timetable and add info on future and past hackathings
Remove timetable and add info on future and past hackathings

The timetable should be just on the eventbrite page for a particular hackathing, as it might be confusing if a specific hackathing differs from the website.

hackathing/hackathing.github.io,hackathing/hackathing.github.io,hackathing/hackathing.github.io