Support for CIP14

[theeldermillenial]

PyCardano does not currently support CIP14, which defines the mechanism for generating assets fingerprints (bech32).

https://developers.cardano.org/docs/governance/cardano-improvement-proposals/cip-0014/

A user requested this in Discord, and I was able to whip up a quick solution. PyCardano has all the necessary pre-requisites to implement this easily. I am posting this here mostly so it doesn't get lost in Discord history. At some point I should open a PR for this under pycardano.cip, but for now here is the quick sample I made up.

from nacl.encoding import RawEncoder
from nacl.hash import blake2b
from pycardano.crypto.bech32 import encode

tests = [
    {
        "policy_id": bytes.fromhex(
            "7eae28af2208be856f7a119668ae52a49b73725e326dc16579dcc373"
        ),
        "asset_name": bytes.fromhex(""),
        "asset_fingerprint": "asset1rjklcrnsdzqp65wjgrg55sy9723kw09mlgvlc3",
    }
]

asset_hash = blake2b(
    tests[0]["policy_id"] + tests[0]["asset_name"],
    digest_size=20,
    encoder=RawEncoder,
)
print(f"Calculated Asset Fingerprint: {encode('asset', asset_hash)}")
print(f"Expected Asset Fingerprint: {tests[0]['asset_fingerprint']}")

I think to finish this off, it should be:

1. wrapped in a function that integrates well with other PyCardano types (i.e. MultiAsset encode/decode similar to Address with bech32 addresses)
2. grab all test cases in CIP14 documentation, and use in unit tests

It's not much work, but I'm swamped right now. If someone want's to take a stab at it, be my guest.