feat: lazy resolver (#4249)

* default to empty `ImmutableMap` when grabbing op metadata
* pass `errors` into JsonSchema components
* Account for Immutable data structure in JavaScriptonSchema...
    ...and create empty Lists instead of Maps by default.
* Pass ImmutableList through to JsonSchema child components
* Add lazy resolving spec state extensions
* TEMPORARY: disable conventional resolved spec
* WIP
* Use resolveSubtree in Operation display
* Freebie: short-circuit Markdown component if it is given plaintext
* NEW DEFAULT BEHAVIOR: `defaultModelsExpandDepth: 1` does not expand individual models
* Render faked Model expander to trigger resolution
* Baseline support for Editor lifecycles
* Display operation summaries before the operation is resolved
* Test migrations
* WIP
* Swagger2 TIO Body params
* a bit of cleanup
* Debounce string param inputs
* Reach into unresolved operation for deprecated flag, if available
* Fire subtree request outside of render
* Remove debugging flags
* Fix logical errors in spec statePlugins
* TODOs become TODONEs!
* Migrate deeplinking feature to non-resolved spec action
* ESLint fixes

test/core/plugins/spec/actions.js

@@ -177,6 +177,10 @@ describe("spec plugin - actions", function(){
     })
   })
 
+  describe("requestResolvedSubtree", () => {
+    it("should return a promise ")
+  })
+
   it.skip("should call errActions.newErr, if the fn.execute rejects", function(){
   })