FX Convertion

[app2let]

FX conversion (and in general, trading Units, such as therms, bbl, tones) support is missing… Would be useful to have for spread trades in different currencies and different units , eg NBP gas in therms in GBP vs TTF gas in MWh in EUR…

[app2let]

@polakowo Is it reasonable to expect vectorbt to be extended to commodity requirement? Otherwise i will try to branch out and try my own version... Currently main commodity features such as FX convertion, spreads, lot size, negative prices are not covered...