Add UI and backend support for creating EGI machine

[ ] User logs in, clicks on some "Create EGI machine" and uploads EGI certificate
[ ] GEF starts a special Docker container that creates the EGI VM, getting back an IP and user account (selected by GEF)
[ ] GEF runs a procedure to configure the Docker connection with EGI
[ ] When starting a service, the user must be able to select the location of the execution: either on the default, common, Docker service; or on the EGI machine

EUDAT-GEF / GEF