Saving & restoring video watching progress

Video progress updates:

- Mark as 'done' when 90% or more is watched.
- Keep 'done' flag when re-watching.

The video progress is stored on three events, whichever comes first:

- Every 30 seconds of video.
- Every 10% of the video.
- Every pause/stop/navigation to another page.
- When we detect the video is looping.

src/templates/nodes/custom/asset/video/view_embed.pug

@@ -67,6 +67,14 @@ script(type="text/javascript").
 		});
 		this.hotkeys();
 
+		{% if current_user.is_authenticated %}
+		let fetch_progress_url = '{{ url_for("users_api.get_video_progress", video_id=node._id) }}';
+		let report_url = '{{ url_for("users_api.set_video_progress", video_id=node._id) }}';
+		this.progressPlugin({
+			'report_url': report_url,
+			'fetch_progress_url': fetch_progress_url,
+		});
+		{% endif %}
 	});
 
 	function addVideoPlayerButton(data) {

src/templates/projects/view.pug

@@ -74,6 +74,7 @@ link(rel="amphtml", href="{{ url_for('nodes.view', node_id=node._id, _external=T
 script(src="{{ url_for('static_pillar', filename='assets/js/vendor/videojs-6.2.8.min.js') }}")
 script(src="{{ url_for('static_pillar', filename='assets/js/vendor/videojs-ga-0.4.2.min.js') }}")
 script(src="{{ url_for('static_pillar', filename='assets/js/vendor/videojs-hotkeys-0.2.20.min.js') }}")
+script(src="{{ url_for('static_pillar', filename='assets/js/video_plugins.min.js') }}")
 | {% endblock %}
 
 | {% block css %}