Move release package to github

[nicolas-bastien]

Description

Releases of ezplatform are stored in ezplatform.com, this ends on a big storage/originals files.

Solution

Github provide the possibility to upload a file for each release adn have an API.

1 - upload releases on github
2 - refactor the downoad block to call github API : https://developer.github.com/v3/repos/releases/
3 - remove releases files from ezplatform.com

[bdunogier]

As I did suggest this, I'm obviously in favour of it.

If we don't do that, the repo is gonna end up completely out of control in terms of download size.