Refactor plotting

[angerhang]

At the moment, the plotting script is a big script clotting together which makes it more cumbersome than ideal to make changes or add features. We need to refactor this badly.

https://github.com/activityMonitoring/biobankAccelerometerAnalysis/blob/master/accelerometer/accPlot.py

[chanshing]

I agree 👍

[chanshing]

@angerhang Would you like to look at accPlot again and have a go? Or @R-Walmsley if interested.

[R-Walmsley]

I know @gmertes is also using this function so cc'ing in case you've already made any changes to your own version.

[gmertes]

My changes are already merged. My only request is to keep the interface to plotTimeSeries the same (or at least backwards compatible), that's the function I'm using.

[chanshing]

Re-open if unresolved.