Added

• Portfolio tracking feature to display holdings, average price, and profit/loss for each ticker (@michal-pielka)
• Configuration support for portfolio holdings in config.yml (@michal-pielka)

Portfolio

Track your portfolio holdings to see profit/loss
Each ticker is tracked with quantity and average purchase price
Ticker symbols must match those in the symbols list in order to be visible

# config.yml
portfolio:
  AMD:
    quantity: 1.3
    average_price: 221
  SPY:
    quantity: 100
    average_price: 450.25

Special thanks to @michal-pielka for this feature