Persist clickstream data for send after tab close

[jbn]

We tried using beacons, but they get blocked too often, making it hard to get some (or any!) information on some user preferences. Now we are back to doing normal fetches. However, this is a problem because it means the video watched before the last tab close doesn't get sent. This is a surprisingly large set of plays.

If possible, I'd like the clickstream data to be stored in state, but get cleared when finalized. That is,

1. When the user is done with a stream, send it and clear that state entry;
2. If it is playing and loaded, periodically flush the information to state, and on the next visit, do (2)

IDK react well enough to know if this is too expensive (cpu/battery) or slow. But even flushing for every 30 seconds of play would be a large improvement for me.

[tzarebczan]

@infinite-persistence wanna take a stab in some of your "spare" time? The idea would be to save the recsys object in redux at some interval, and clear out once sent. If it's not sent, on subsequent start-up, send it, and clear from redux.

I asked @jbn to see if we should send some additional flag to tag these.

[infinite-persistence]

Sure, will try!