proxy ATVSettings to std+SSL WebServer/XMLConvert

- move responsibility for ATVSettings to PlexConnect.py main code
- align WebServer/SSL Webserver to equally serve requests
- see
https://forums.plex.tv/index.php/topic/120584-plexconnect-on-atv-70-gm-i
os-80-gm/?p=723474 for the principal structure