it seems like the job name is important

this way master branch will be accessible

on debian-like systems, python is python3

HTML_BASEURL now depends on the platform

you can use the new `make clean_install` for that

it will now be get_globals.py

- moved `versions.json` to root dir
- renamed `versions.json` to `globals.json`
- add available platforms/versions/language in `globals.json`

Right now, this file is used for the tab menu selection only.

But, this could be used (and will be soon) for other purposes:
- default version redirection for each platform
- more automated CI generation (for languages for example)

Everything related to desktop will be stored in desktop/* branches

in the future it could be replaced by regex

branches should now add the platform in their name.
Example: branch 'desktop/3.0' is the version 3.0 of platform desktop.