Change verify function visibility from external to public to enable inheritance

[Turupawn]

The problem

It should be common for devs to inherit from UltraVerifier while creating a dApp. This is to keep the codebase organized and readable. A normal implementation should look like the following example:

//SPDX-License-Identifier: MIT
pragma solidity >=0.8.19;

contract MyDApp is UltraVerifier {
    // Custom logic
    function proveStuff(bytes calldata _proof, bytes32[] calldata _publicInputs) public {
        verify(_proof, _publicInputs));
        // More custom logic
    }
}

However this is currently not possible due to the verify function being external. This means that this function is not visible to inherited contracts.

The solution

I think the verify visibility should be changed to public. This will enable verify being called from inherited contracts like the example above.

[TomAFrench]

Hi @Turupawn, the verifier contracts aren't actually developed/tested in this repository but in https://github.com/AztecProtocol/aztec-verifier-contracts and so we'd like to ensure that we don't introduce any changes relative to that repository. For that reason I'm going to close this PR as it stands.

However please feel free to open an issue/PR on that repository to discuss with the team which develops the verifier smart contracts. We'll then update to pull down any changes they make.

[TomAFrench]

Sorry for any time wasted by this, I'll make a note in the readme about the repository for the verifier contracts.

[Turupawn]

Thanks @TomAFrench , moved it there:
AztecProtocol/aztec-verifier-contracts#24
AztecProtocol/aztec-verifier-contracts#23