Going through multiple reverse proxy will store multiple scheme and port in HTTP header separated by a comma. Shaarli will use the first one to generate server_url.
HttpUtils.php
Relates to #333 Modifications: - refactor server URL utility functions - do not access global `$_SERVER` variables - add test coverage - improve readability - apply coding conventions Signed-off-by: VirtualTam <virtualtam@flibidi.net>