feat(precompile): Shampoo/plr 100 allow explicit return types in precompile functions

[shampoobera]

functions returning structs are still a WIP-- we can use reflect in order to dynamically convert types so users don't need to. for now, we just return the abigen go bindings. also need to validate return types so they match the ABI's by using reflect.FieldByName and making sure they all match.

[linear]

PLR-100 Allow explicit return types in precompile functions

Instead of returning ([]any, error), make it so that we can return exactly what the solidity function's return type is, e.g. (*big.Int, error) for a solidity function that returns (uint256)