Add terms for some hashing functions

[simleo]

Fixes #14

I've decided to go with a small set of popular algorithms, to avoid bloating the namespace with a ton of new terms. If there is need for others that are not being added here, we can add them later. For the record, here's a list of what Python 3.10 supports:

>>> import hashlib
>>> for s in sorted(hashlib.algorithms_available): print(s)
... 
blake2b
blake2s
md4
md5
md5-sha1
ripemd160
sha1
sha224
sha256
sha384
sha3_224
sha3_256
sha3_384
sha3_512
sha512
sha512_224
sha512_256
shake_128
shake_256
sm3
whirlpool

[simleo]

For instance:

{
    "@context": [
        "https://w3id.org/ro/crate/1.1/context",
        {
            "sha1": "https://w3id.org/ro/terms/workflow-run#sha1"
        }
    ],
    "@graph": [
        ...
        {
            "@id": "foo.txt",
            "@type": "File",
            "sha1": "5b96d8196aba2f47e5b63fa3f5ddbe8c1f927435"
        },
        ...
    ]
}