fix: oas compliance in response schemas

[walker-tx]

This PR:

• Removes $id fields from the various places that they were popping up
• Parses Model[] schema names to:

{ 
  "type": "array",
  "items": { "$ref": "#/components/schemas/Model" }
}

• Adds a test to check for OAS validity when the spec has component/schemas in it

[Lolotronop]

This seems like a generally better written and considered version of my "small additions" to the #219, it should be merged instead of my changes on that for sure, tho standalone validator support portion of that still stands. Probably should have filed those as separate PRs, but oh well. Thanks for doing this!
Your versions also does rewrite the code path with the good old if statements instead of that nasty giant ternary, which is nice. I didn't do that to not break out of the general code style, it seems like Aom likes these ternaries for some reason. Or doesn't care enough to refactor them when they get to big. Either is fine, but yeah :)