support adaptive learning rates in visualization

[gfrogat]

we should at least support simple learning rate decay
Show learning rate plot under the chart detail view

[thinkh]

@gfrogat Do we still need this for the paper?

[gfrogat]

I'll work on some prototypes this week, we can then decide whether we'll consider it for the paper

[thinkh]

The learning rates could be added if we expand the timeline and show curves for every run.