Exercise : BankAccount transactionFee

• Write a method transactionFee to go in the BankAccount class. It takes a fee (real number) parameter and applies the fee to all past transactions. The fee is applied once for the first transaction, 2x for the second, 3x for the third, etc. These fees are subtracted from the account's balance.
• If the balance is large enough to afford all fees with > $0.00 remaining, the method returns true. If not, the balance is 0.0 and it returns false. For example:

  BankAccount savings = new BankAccount("Jimmy", 0.00);
  savings.deposit(10.00);
  savings.deposit(50.00);
  savings.deposit(10.00);
  savings.deposit(70.00);         // balance = $140, with 4 transactions
  
  savings.transactionFee(5.00);   // deducts  $5+10+15+20; balance = $90; returns true
  savings.transactionFee(10.00);  // deducts $10+20+30+40; balance =  $0; returns false