pooling all content into one .md file

[jcolomb]

To push content in the book, it would be best to get all content into one file.

We can probably get a small code doing that (?)

[Protohedgehog]

We can dump it all here once it's been finalised :) https://github.com/OpenScienceMOOC/Module-6-Open-Access-to-Research-Papers/blob/master/content_development/0_MAIN.md