chore: remove redundant CSS editors (microsoft#4092)

# Description

<!--- Describe your changes. -->
This is the removal of the components `<CSSEditor />` and `<CSSPropertyEditor />` both of which were not exported after the shift to v2.0, they are being removed now due to careful consideration on a CSS solution for the tooling which is outlined in microsoft#3773

## Issue type checklist

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- [x] **Chore**: A change that does not impact distributed packages.
- [ ] **Bug fix**: A change that fixes an issue, link to the issue above.
- [ ] **New feature**: A change that adds functionality.

**Is this a breaking change?**
- [ ] This change causes current functionality to break.

<!--- If yes, describe the impact. -->

**Adding or modifying component(s) in `@microsoft/fast-components` checklist**

<!-- Do your changes add or modify components in the @microsoft/fast-components package? Put an x in the box that applies: -->

- [ ] I have added a new component
- [ ] I have modified an existing component
- [ ] I have updated the [definition file](https://github.com/Microsoft/fast/blob/master/packages/web-components/fast-components/CONTRIBUTING.md#definition)
- [ ] I have updated the [configuration file](https://github.com/Microsoft/fast/blob/master/packages/web-components/fast-components/CONTRIBUTING.md#configuration)

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- [ ] I have added tests for my changes.
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packages/tooling/fast-tooling-react/app/app.tsx

@@ -3,11 +3,8 @@ import { BrowserRouter, Link, Redirect, Route, Switch } from "react-router-dom";
 import { NavigationTestPage } from "./pages/navigation";
 import ViewerPage from "./pages/viewer";
 import ViewerContentPage from "./pages/viewer/content";
-import { CSSEditorTestPage } from "./pages/css-editor";
-import { StyleEditorsTestPage } from "./pages/style-editors";
 import { FormTestPage } from "./pages/form";
 import { FormAndNavigationTestPage } from "./pages/form-and-navigation";
-import { CSSPropertyEditorTestPage } from "./pages/css-property-editor";
 import { NavigationMenuTestPage } from "./pages/navigation-menu";
 import { WebComponentTestPage } from "./pages/web-components";
 import WebComponentViewerContent from "./pages/web-components/web-component-viewer-content";
@@ -24,21 +21,6 @@ class App extends React.Component<{}, {}> {
                             path={"/navigation-menu"}
                             component={NavigationMenuTestPage}
                         />
-                        <Route
-                            exact={true}
-                            path={"/css-editor"}
-                            component={CSSEditorTestPage}
-                        />
-                        <Route
-                            exact={true}
-                            path={"/css-property-editor"}
-                            component={CSSPropertyEditorTestPage}
-                        />
-                        <Route
-                            exact={true}
-                            path={"/style-editors"}
-                            component={StyleEditorsTestPage}
-                        />
                         <Route
                             exact={true}
                             path={"/navigation"}
@@ -67,7 +49,7 @@ class App extends React.Component<{}, {}> {
                             component={WebComponentViewerContent}
                         />
                         <Route exact={true} path={"/"}>
-                            <Redirect to={"/web-components"} />
+                            <Redirect to={"/form"} />
                         </Route>
                     </Switch>
                 </div>
@@ -83,15 +65,6 @@ class App extends React.Component<{}, {}> {
                         <li>
                             <Link to="/navigation-menu">Navigation Menu</Link>
                         </li>
-                        <li>
-                            <Link to="/css-editor">CSS Editor</Link>
-                        </li>
-                        <li>
-                            <Link to="/css-property-editor">CSS Property Editor</Link>
-                        </li>
-                        <li>
-                            <Link to="/style-editors">Style Editors</Link>
-                        </li>
                         <li>
                             <Link to="/form">Form</Link>
                         </li>

packages/tooling/fast-tooling-react/package.json

@@ -47,8 +47,8 @@
     "coverageThreshold": {
       "global": {
         "statements": 80,
-        "branches": 60,
-        "functions": 77,
+        "branches": 59,
+        "functions": 76,
         "lines": 80
       }
     },