This reverts commit 4f889d20.

[FEATURE] Properly cache the youtube thumbnail and deliver that as a picture tag (heavy performance improvement)

Change the way the YouTube API is called to RequestFactory,
because we do not want to care manually what method of
fetching urls is available on the server.

[FEATURE] Add new options to the plugin: thumbnail type, aspect Ratio, debug output & add intelligent thumbnail analyse feature as default & several bugfixes and cleanups