aarchmrs-instructions: extract instructions' required HW features (and other conditions)

[monoid]

Conditions are stored in the "condition" field. They are logical expressions, and some of them are "IsFeatureImplemented" invocations or their combinations.

"condition": {
  "_type": "AST.Function",
  "arguments": [
    {
      "_type": "AST.Identifier",
      "value": "FEAT_MTE"
    }
  ],
  "name": "IsFeatureImplemented",
  "parameters": []
}