Add a distance viewing mode

The workout screen is still quite hard to make out from a distance, and could make more use of the full height of the screen. In particular, it's hard to see the current rep.

I don't feel like the total time is really that relevant during a workout - I want to know how long is left of the current rep, is there another rep afterwards, and (am I/can I please be) on the last set?

```
Set Rep
111 222
111 222
---------
Break
---------
000:111
000:111
```