Standardize Pool approval amounts

[defispartan]

supply, repay, repayWithPermit, and supplyWithPermit are all approving underlying tokens to the Pool contract. Some approvals use a max approval while others use per-tx allowance. This should be standardized or give the option to select max approval vs per-tx.

[JoaquinBattilana]

Hey just to add some context to this, there are some cases that we absolutely need max approval, for example for repayWithPermit if you want to do a max repay you need to pass a signature with max approval because it validates it in the contracts