fix #6 Migration to Gitlab in the Readme
- Added the location for the issues
- Added the location for MR's
- I wrote the URL in full because
- We have a mirror on github, adding the full URL makes it more explicit that MR's need to be done on another repo
- Advertising GAFAM free platforms ;)
- I also use this MR to start using a develop branch and added this to the README
- I also removed how to install from the web interface because ynh has removed the possibility to add custom lists from the webinterface