housekeeping: bundle size reductions (#4713)

* set new bundlesize goal
* preserve `GeneratorFunction` instead of all function names
* use js-yaml fork that doesn't require esprima
* set HTML content directly, instead of using React-Markdown
* use remarkable for all Markdown rendering
* add babel-plugin-transform-react-remove-prop-types
* remove SplitPaneMode plugin
* remove react-collapse
* remove AST plugin, and yaml-js
* trim Markdown HTML string output before rendering
* disable obsolete function name preservation
* add `getComponent` to propTypes

src/core/components/auth/authorization-popup.jsx

@@ -9,7 +9,7 @@ export default class AuthorizationPopup extends React.Component {
   }
 
   render() {
-    let { authSelectors, authActions, getComponent, errSelectors, specSelectors, fn: { AST } } = this.props
+    let { authSelectors, authActions, getComponent, errSelectors, specSelectors, fn: { AST = {} } } = this.props
     let definitions = authSelectors.shownDefinitions()
     const Auths = getComponent("auths")