Start pairing trades through transfers

[DeirhX]

• Transfers between accounts we already imported can be ignored for the pairing algorithm
• Transfers from outside accounts need their proceeds / purchase prices to be input somehow

[DeirhX]

Editor to add transfer sources added.

Now we need to solve that adding missing transfer sources messes up the total count. However, those are purchases on other accounts. Maybe we should favor Account Accumulated Quantity for most computations to Accumulated Quantity?