BIP-352: use own ripemd160 for reference implementation

On some operating systems, Python doesn't provide the expected ripemd160 implementation anymore, so the reference implementation fails to start. E.g. in Ubuntu 22.04:

$ ./reference.py send_and_receive_test_vectors.json
Simple send: two inputs
Traceback (most recent call last):
  File "/usr/lib/python3.10/hashlib.py", line 160, in __hash_new
    return _hashlib.new(name, data, **kwargs)
ValueError: [digital envelope routines] unsupported

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/thestack/bips/bip-0352/./reference.py", line 228, in <module>
    pubkey = get_pubkey_from_input(vin)
  File "/home/thestack/bips/bip-0352/./reference.py", line 46, in get_pubkey_from_input
    pubkey_hash = hash160(pubkey_bytes)
  File "/home/thestack/bips/bip-0352/bitcoin_utils.py", line 130, in hash160
    return hashlib.new("ripemd160", hashlib.sha256(s).digest()).digest()
  File "/usr/lib/python3.10/hashlib.py", line 166, in __hash_new
    return __get_builtin_constructor(name)(data)
  File "/usr/lib/python3.10/hashlib.py", line 123, in __get_builtin_constructor
    raise ValueError('unsupported hash type ' + name)
ValueError: unsupported hash type ripemd160

Fix this by providing a manual implementation, taken from the functional test framework of Bitcoin Core. See corresponding issue https://github.com/bitcoin/bitcoin/issues/23710 and PR https://github.com/bitcoin/bitcoin/pull/23716.