Add new content types

Add new content types :
Article
Book
Course
Dataset
Event
Fast Check...

[rudza]

Offer (https://schema.org/Offer)

Or teach us how to do it :)

[laradevitt]

Posting this 'Event' example in case it helps anyone: https://gist.github.com/laradevitt/54e9125a086c80d8178bc5cdcc77c25c