add derived data series to statements of assets chart

[mierin12]

Hello, same as #4235 that I was not able to maintain by rebase, I manage to be up to date by squashing its commits.
So now this PR present a single clear commit rather than an history of WIP commits that I could not maintain.

Goal : derived data series are available in the associated widget but it does not allow to compare different data series and is not customizable (color). By adding the derived data series to the statement of assets chart, this is possible.
Exemple : comparison of Delta of different data series :

Based on #3754

[buchen]

@mierin12 thanks for the hard work in refactoring the change (and the patience to see it through).

I like the approach (new type, separate dialog).

Please have a look at #4403. Based your code, I did some more refactored:

• First, I renamed the objects and types to be "derived" and "aspect" (similar to the widget on the dashboard)
• Second, the DerivedDataSeries is now an object that holds the reference to the underlying data series (base) and the aspect to be used. This way, we can re-used the (potentially) already cached data series.
• Third, I now create the data series based on the already created underlying data series.

If you have time, I would appreciate if you can have a look