Make.SWeb host, that should be used in access control headers, if specified. If web_host isn't specified, then acces-control header in response will be set to '*' and authentication wwith cookies wouldn't work. Note : Cookies would be set by browser only if request's flag 'with_credentials' is set to true. Last one in turn, requires that "Access-control_allow_origin" header by reponse returns something different from "*".
val user_id_encoding : user_id Json_encoding.encodingJson encoding for user's id
val user_info_encoding : user_info Json_encoding.encodingJson encoding for user's information
RPC path where authentication services like connect, login and logout would be placed.