Closes #4503

Hello,

This is a proposition to add the Capital Gains as per Moving Average cost method in :

• The Performance Calculation view
• The Performance Calculation widget
• The Securities Performance view (more columns)

FIFO remains per default in the Performance Calculation view and widget.

There were already Calculation Gains as per Moving Average in the Securities Performance view, but only on the 'current holdings'.

Performance Calculation view

Securities Performance view

Performance Calculation widget

Forex Gain : added, but I am not 100% confident on it. I wanted to add tests, but I did not managed to understand how to correctly represent the transactions in the test. Neither the transactions directly in the forex currency, neither the ones with an exchange rate.

Trail Record for the tooltip : I need to deep dive into it, to see first if the exact same structure can be reused or if it is custom made for FIFO. I propose to look into it in a second step.

Transfer : unsure if something has to be done here ? In the CostCalculation.class, the Transfer is only used for FIFO cost.
For the new class CapitalGainsCalculationMovingAverage, I used a bit of CostCalculation and CapitalGainsCalculation logics.

I took the opportunity to add Descriptions to those columns of Securities Performance view.