cumulative support for history line charts

[sgratzl]

Prerequisites:

• Unless it is a hotfix it should be merged against the dev branch
• Branch is up-to-date with the branch to be merged with, i.e. dev
• Build is successful
• Code is cleaned up and formatted

Summary

add support to show the raw cumulative signal version for cases/deaths. part of #928

note: the dark green portion is the amount that has been added for this day

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[krivard]

While "cumulated" is a legit word, it tends to be reserved for far more technical contexts than we need here. Use "cumulative" instead.

I don't understand what "raw: 16.6" means in the caption, since the cumulative data is also raw (unsmoothed). do you mean "incident"? "new" would also work there

[sgratzl]

so far: raw = unsmoothed and cumulative = unsmoothed cumulative. I don't know whether new or incident would be more clear in this case

[sgratzl]

While "cumulated" is a legit word, it tends to be reserved for far more technical contexts than we need here. Use "cumulative" instead.

done