Decouple resource provider registration

apps/files/lib/AppInfo/Application.php

lib/composer/composer/autoload_classmap.php

lib/composer/composer/autoload_static.php

lib/private/AppFramework/DependencyInjection/DIContainer.php

lib/private/Collaboration/Resources/Manager.php

lib/private/Collaboration/Resources/ProviderManager.php

lib/private/Server.php

lib/public/Collaboration/Resources/IManager.php

lib/public/Collaboration/Resources/IProviderManager.php

tests/lib/Collaboration/Resources/ManagerTest.php

tests/lib/Collaboration/Resources/ProviderManagerTest.php