Beedle - Oracle free perpetual lending

1. For the borrow() & repay() in Lender.sol the public visibility modifiers should be changed to external, to help optimize gas usage. Since it doesn't seem these functions are called internally at all, external modifier should be sufficient.

https://github.com/Cyfrin/2023-07-beedle/blob/d9718f2ca6521756624c017c90f3d4d4e80da90c/src/Lender.sol#L232
https://github.com/Cyfrin/2023-07-beedle/blob/d9718f2ca6521756624c017c90f3d4d4e80da90c/src/Lender.sol#L292

Recommendation:

Change from:

function borrow(Borrow[] calldata borrows) public {
and
function repay(uint256[] calldata loanIds) public {
and
function startAuction(uint256[] calldata loanIds) public {

to:

function borrow(Borrow[] calldata borrows) external {
and
function repay(uint256[] calldata loanIds) external {
and
function startAuction(uint256[] calldata loanIds) external {