Add trading stats to the PDF report

Add a new section in the PDF strategy reports with the following statistics:

Realized Trades Stats (since inception)

All Winners Losers
Trades 200 120 (60%) 80 (40%)
Avg Return % 5.1% 8.0% -3.2%
Avg Days 30 45 20

NOTE: currently realized trades do not include dividends. This is being addressed in a separate task.

Thank you.