Add fee

[Samyak Jain]

A fee variable. Just like Aave flashloan. 1 = 1 BPS = 0.01% fee. 9 = 9 BPS = 0.09% fee.

The fee will be net. Eg:-
Let's say we set the fee at 5 BPS. If the flashloan fee is 2 BPS then we will only charge 3 BPS so net equals 5 BPS.
If the flashloan fee is already >=5 BPS. Eg:- Aave has 9 BPS then we won't charge anything in that case.