feat: built-in HLS playback support

[forbesjo]

Description

This PR is to start the conversation for adding HLS playback support built into video.js for 7.0 via videojs-http-streaming (shorthand VHS). VHS is the next major version of videojs-contrib-hls that removes HLS Flash playback and includes some experimental DASH support (hence the rename). The purpose is to improve the out-of-the-box experience for video.js and allow cross browser HLS compatibility.

Todos:

• Resolve the webworkify issue in order to support webpack Support for webpack? videojs-contrib-hls#600
• Determine how we'll create builds with and without VHS (if a user prefers to use hls.js)
• Resolve any API changes video.js requires and version 1.0.0 VHS

Requirements Checklist

• Feature implemented / Bug fixed
• If necessary, more likely in a feature request than a bug fix
  • Change has been verified in an actual browser (Chome, Firefox, IE)
  • Unit Tests updated or fixed
  • Docs/guides updated
  • Example created (starter template on JSBin)
• Reviewed by Two Core Contributors

[gkatsev]

Looks like there are other, potentially related issues with the build: https://travis-ci.org/videojs/video.js/builds/342401866#L3557
but hurray for getting things started!

[forbesjo]

Since the webworker plugin will only work with browserify and webpack let's consider switching from rollup to webpack in video.js

[brandonocasey]

started some webpack work awhile ago in #4985

[gkatsev]

Thanks @brandonocasey. I'm going to be switching to webpack work tomorrow.

[forbesjo]

Closing in favor of #5053