Add support for click-to-hold-focus in ToD view

[simonhac]

When inspecting a specific time of day in ToD view, the user really needs to be able to click to hold the focus on a specific moment.

…and the line (focus period) should probably be replicated in the charts below — with the average for that specific time displayed in all tooltips.

Currently if we're showing the specific time average in one chart, we don't show it in the others:

[aleith]

I think this is same issue I'm experiencing … users need to be able to 'click' and 'stick' on any given day item in the date listing when the dates are listed in expanded field:

as soon as your cursor moves away from the date of interest in this list then the graph impression changes to either some other day(s) or defaults back to average and greyed out sample data for 7D, 14D or 30D.

the list works fine, but needs a way to lock and unlock the date selection in.