Support indy 1.16 predicate restrictions

[sklump]

Still to work out:

• general WQL (+ "$and") for restrictions in proof request requested attributes/predicates
• not necessarily relying on these being a list: they can be a (WQL statement) dict or a list of (WQL statement) dicts, each (WQL statement) dict possibly being its own compound WQL statement; e.g., this is a valid restriction:

{
  "$and": [
    {
      "$or": [
        {
          "schema_name": "membership"
        },
        {
          "schema_name": "members"
        }
      ]
    },
    {
      "$neq": {
        "schema_version": "0.1"
      }
    },
    {
      "issuer_did": "abc123"
    },
    {
      "$not": {
        "$in": {
          "attr::name::value": [
            "joe",
            "dolly",
            "bill"
          ]
        }
      }
    }
  ]
}

[sklump]

Reference: https://hyperledger-indy.readthedocs.io/projects/sdk/en/latest/docs/design/011-wallet-query-language/README.html

But "$and" is in the code where it's implicit in the standard.

[codecov-commenter]

Codecov Report

Merging #1213 (a0c1236) into main (2b54294) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1213      +/-   ##
==========================================
- Coverage   98.47%   98.47%   -0.01%     
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  Files         456      456              
  Lines       25431    25428       -3     
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- Hits        25042    25039       -3     
  Misses        389      389