Retrieving the discrete concentration time series data to calculate the

value for the exceedance plot. Also did some rearranging of the code in
main.js so that code that can run before the siteInfo is done outside of
the promise resolution.
I thought about it. I'd have to refactor this part of the code to do that, probably by moving the calculation to ExceedancePlot.js (which at the moment has not tests). I may do this if I have time at the end of the iteration.