add QT and check playable

[HanaGemela]

No description provided.

[jnweiger]

QT is QuickTime, here :-) -- just saying for all you Qt-people out there.

@mmattel Do we also want to add video/mpeg ?
For ogg-theora, I know that a fallback to application/ogg is used, not sure if such things should also be listed here.

[mmattel]

We can add any mime we want as long it starts with video easily.

Yes, mpegis a good idea.

Correction: mpeg does not have it's own mimetype, pls see
https://www.iana.org/assignments/media-types/media-types.xhtml

The new code for video can be extended/changed to add more basic types.
I have build the code around a mime starting with video because the check itself should only be targeted for those kind of mimes if they are playable in the browser. The code may have to be adopted to reflect that other mimes not starting with video are checked if playable (video, audio).