[Bug-Candidate]: Functions with the same signature can be generated multiple times

### Describe the issue:

When multiple contracts have functions with the same signature fuzz-utils will generate the same function multiple times, preventing compilation.

We should:
- Add a prefix to the function e.g., `contractName_functionName` when generating
- Detect if a function is overriden and only generate one instance in that case

### Code example to reproduce the issue:

```solidity
contract A {
function transferFrom(address from, address to, uint256 amount) public virtual returns (bool) {
// Do something
}
}

contract B is A {
function transferFrom(address from, address to, uint256 amount) public virtual override returns (bool) {
// Do something else
}
}
```

### Version:

0.2.0

### Relevant log output:

```shell
N/A
```