Rename ssl and auth configuration file settings.

Add enable SSL config validator.
Strict configuration file validation: any error will prevent the server to start.
Core server logic moved to a Server class.

conf/gns3_server.conf

@@ -12,7 +12,7 @@ port = 3080
 secrets_dir = /home/gns3/.config/GNS3/secrets
 
 ; Options to enable SSL encryption
-ssl = False
+enable_ssl = False
 certfile = /home/gns3/.config/GNS3/ssl/server.cert
 certkey = /home/gns3/.config/GNS3/ssl/server.key
 
@@ -58,7 +58,7 @@ udp_end_port_range = 30000
 ;ubridge_path = ubridge
 
 ; Option to enable HTTP authentication.
-auth = False
+enable_http_auth = False
 ; Username for HTTP authentication.
 user = gns3
 ; Password for HTTP authentication.
@@ -78,7 +78,6 @@ jwt_secret_key = efd08eccec3bd0a1be2e086670e5efa90969c68d07e072d7354a76cea5e33d4
 jwt_algorithm = HS256
 jwt_access_token_expire_minutes = 1440
 
-
 [VPCS]
 ; VPCS executable location, default: search in PATH
 ;vpcs_path = vpcs