Community section improvements (Including articles page) (#421)

* Added youtube thumbnails to education page

* Added on rails and ken greef to youtube channels

* Removed Modern Application Development with Rails as it is no longer for sale

* Removed Turbo native workshop, as it is sold out

* Typo in youtube channels

* Converted courses to a grid

Added course pricing

* Added Sam Johnson to youtube channels

* Added articles to articles page

plus a couple of helpers

* Added some books refrerenced in the newsletter

* Added railsquest to youtube channels

* Adding updated articles list

* Added some additional tutorials

* Added some additional tutorials

Typo

* Youtube -> YouTube

---------

Co-authored-by: Marco Roth <marco.roth@intergga.ch>

Author: TeriyakiBomb