Implement remote cron as api task (more to come)

 - local piping must use api/pipe.php
 - API Key is not required - bypasses TicketApiController::create
 - Overwrites ApiController's response method -  postfix exit codes are used as opposed to http codes

Add special case and helper method to process emails

Before it required an edit for osTicket installations made to a folder other
than the root of a domain or subdomain. Now, the installation path is
autodetected and rewritted.

Also, don't assume that every Apache installation has mod_rewrite support.

There are no symlinks in the api/ folder or subfolder

The API is implemented for HTTP requests via the api/http.php module.  Where
supported (by Apache), support rewriting URIs from something like
http://domain.tld/api/tickets.xml to
http://domain.tld/api/http.php/tickets.xml, so the explicit usage of the
http.php script is not required.