Move socket_type in another module and use another of tuple of tuple of tuple in extract_info
New module (same as ocsigen 3.0.0) for handle socket type
New module to configure a server
Use Ocsigen_socket.socket_type instead Ocsigen_parseconfig.socket_type and use new module Ocsigen_server_configuration for create a new server
Aftereffect of last commit (use Ocsigen_server_configuration now)