Add ability to record account audits

[VMelnalksnis]

Is your feature request related to a problem? Please describe.
This is mostly an issue for cash accounts, since all transactions from bank accounts are recorded, or when starting to record transactions. The problem is that after adding all transfers the account balance does not match reality.

Describe the solution you'd like
It is possible to link an audit entity to an account in currency, which would specify the actual balance at a specific time. These audits would also have to be taken into account in reports.

Describe alternatives you've considered
A simpler alternative is to just to use a transaction, and specify Audit for each currency as the purchase product. Maybe a simpler editor should be provided for such cases, but it would not introduce additional complexity in other places.