Add a bank to do transactions

[Seniru]

Banks are essential when doing business activites. So it'd be better if we added a bank to the game. By implementing the bank, we are planned to allow players to

• Deposit money
• Withdraw money
• Obtain loans
• Transfer funds (lots of players are talking about donations, so this could be useful)

[Seniru]

Issue was closed by mistake. Let's reopen it :P