Twenty Seventeen: Consider removing custom header from internal pages if selected video header

[karmatosed]

This came up as I first off didn't even notice I still had default custom header until went to that blog page on the front end.

It felt logical to me that the video header I had set would continue in the main site or at least I'd not still see the default header image.

[xkon]

Option to apply video header in internal pages

[xkon]

This made sense to me as well after building a couple of websites with 2017 that might have the need to use the video everywhere.

39623.diff adds an extra option under the Theme Options in Customizer to apply the video in all pages instead of only the front page. Some users might still want the video on the front page only that's why I made it as an extra option instead of forcing it.

It is working ( the video is applied everywhere ) but the CSS is missing as that part got me a bit confused, if someone wants to tackle the CSS changes required for this it would be awesome.

Also a question came up when I was doing this: on the internal pages there is an extra 'header' with the featured image. Should that stay as is? Or if the video is to be played everywhere we should also cancel the featured image header ? I'm asking because if you see a full screen video + the header featured image the scroll down to content would be long I imagine.

(Note: For my websites purposes I have added extra css with a not-so-proper-way to bypass the default styling and have the video applied properly + hidden the featured image completely if the video is applied. )