Discard and landings TS in plots

[villy]

On the group plots the total discards plot should show the modeled discard amount along with the reference data (somehow). The plots should be cumulative so we'll have to have colors stacked on top of each other, and the reference data in the same order as dots. Same for landing. and the total catch now shows cumulative catch, but not the cumulative sum of landings and discards.

Presume discard survival should be cumulative as well