Keep all past farm events with default display position at the next farm event

Before this feature is tackled, there should probably be a resolution to if we think its a good idea to [move event calculation out of FBOS and into the API](https://github.com/FarmBot/Farmbot-Web-App/issues/1477).

### Calendar

```
past farm event
past farm event
past farm event
--- starting top scroll position/colored line ---
currently executing event (when applicable)
future farm event
future farm event
future farm event
```

Past farm events should be slightly grayed out, and there should be a colored horizontal line indicating the division between past and future events. A related feature is [highlighting the currently executing event](https://github.com/FarmBot/Farmbot-Web-App/issues/1470), which should be the one directly under the colored line.

Perhaps there should be no edit button on mouse-over for past events? Thoughts?

FBOS should ideally _not_ sync expired events (events with nothing left to run).