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": []
}