Updated video.js to version 7.6.5

Plugins:
* videojs-contrib-hls: Dropped for native hls/dash support
* videojs-resolution-switcher: No longer maintained. Manually fixed to
work with new version
* videojs-markers: No longer maintained. Still works as expected.
* videojs-hotkeys: Updated

The (manually fixed) resolution switcher still looks a bit different.
Also video.js dropped support for older Internet Explorer and their
flash support.