[appserver-io/appserver] PHP process wrapper

[wick-ed]

Currently the runtime offers different processes (e.g. php-fpm, php, ...). To further improve the usability of these processes we might wrap them in a PHP layer to be able to control them from within the appserver.

UAC:

• There MUST be a possibility to at least enable "start", "stop" and "status" like functionality for processes within PHP

[wick-ed]

@see https://github.com/symfony/Process