Differentiate personal accounts even further

[simhnna]

The main goal would be to differentiate between these account types:

• checking
• saving
• cash
• credit card

With that we can do fancier stuff like:

• Not count cash into the balance (cash is easy to loose and it's hard to keep the account correct)
• keep out credit cards from the account balance charts because they just cause noise
• Differentiate balance based on it being in a saving account or not
• ...