Add an "algorithms" field to all problem documents, but tag it so it
won't be included in the serialized json unless populated. Populate it
only when the problem type is "badSignatureAlgorithm", as specified in
RFC 8555 Section 6.2.
The resulting problem document looks like this:
```json
{
"type": "urn:ietf:params:acme:error:badSignatureAlgorithm",
"detail": "Unable to validate JWS :: JWS signature header contains unsupported algorithm
\"RS512\", expected one of [RS256 ES256 ES384 ES512]",
"status": 400,
"algorithms": [
"RS256",
"ES256",
"ES384",
"ES512"
]
}
```
Fixes https://github.com/letsencrypt/boulder/issues/8155
f86f88d563