Image capture should use standard UserMedia API

[jonathanaustin]

Image capture currently uses a getUserMedia js library to handle the image capture APIs for different browsers. This library was very handy when the UserMedia API was still being worked out and was not standard across browsers.

However, browsers have now all come inline with supporting the standard UserMedia API but the getUserMedia js library does not support the new API. This means image capture does not work reliably in all browsers and does not work at all in Safari.

To fix this, we should look at removing the getUserMedia js library and just use the standard UserMedia API directly or add the UserMedia API support to the library.

At the same time, we should also make sure the image capture button only appears on desktops as it is not required on mobiles or tablets as image capture is provided by their file upload.