Target information on watchlist table

[horvathmarton]

Description

Add valid next target information to the watchlist table.

Technical details

• Add an endpoint to fetch current stock prices for a list of stocks.
• Add a service for target calculation.
• We should match the current price with the closest target price (if applicable).
• We should match the current position size with the closest position size target (if applicable).
• Display the result on the watchlist table.