Take advantage of autoloaders for including new Ad Servers

[jomurgel]

Reference #82

Composer has support for generating an autoloader for you so you can "just use" the class and it will load the file on demand.

We'd probably need a class-map autoloader. https://getcomposer.org/doc/04-schema.md#classmap

The downside to a class-map autoloader is that it's really unintelligent and needs to be regenerated when you add a new file or rename an existing file. In OO programming where you potentially are creating new classes all the time, that's a hassle and so PSR-4 and PSR-12 were adopted so that loading classes can be inferred by convention. https://www.php-fig.org/psr/psr-4/