Add chart syncing

[neilrqm]

One advantage (and disadvantage) of building charts on Google Sheets is that when somebody changes the configuration the chart gets updated for everyone. It may be valuable to add that functionality to this charting tool. First we want to check to see if this is worth doing. If it is, then we can implement. One thought is to have a second "create link" button that creates a "live link" that can be shared. Perhaps this link could function like Google Meet, where any string can be the index for a live session. The canonical state for each client that opens this link is stored in the API and pushed (via websocket?) every time it changes.