[Glitch] Responsively enforce 16:9 ratio on video thumbnails in web UI

Port the video-player part of 036dd98abb to
glitch-soc. MediaGallery part ignored since it has diverged quite a bit.

This fixes #423

app/javascript/flavours/glitch/components/status.js

@@ -326,6 +326,7 @@ export default class Status extends ImmutablePureComponent {
             {Component => (<Component
               preview={video.get('preview_url')}
               src={video.get('url')}
+              inline
               sensitive={status.get('sensitive')}
               letterbox={settings.getIn(['media', 'letterbox'])}
               fullwidth={settings.getIn(['media', 'fullwidth'])}