Make code prettier

This updates ESLint and our shared eslint-config-openlayers to use Prettier.  Most formatting changes were automatically applied with this:

    npm run lint -- --fix

A few manual changes were required:

 * In `examples/offscreen-canvas.js`, the `//eslint-disable-line` comment needed to be moved to the appropriate line to disable the error about the `'worker-loader!./offscreen-canvas.worker.js'` import.
 * In `examples/webpack/exapmle-builder.js`, spaces could not be added after a couple `function`s for some reason.  While editing this, I reworked `ExampleBuilder` to be a class.
 * In `src/ol/format/WMSGetFeatureInfo.js`, the `// @ts-ignore` comment needed to be moved down one line so it applied to the `parsersNS` argument.

examples/custom-controls.js

@@ -1,16 +1,14 @@
 import Map from '../src/ol/Map.js';
-import View from '../src/ol/View.js';
-import {defaults as defaultControls, Control} from '../src/ol/control.js';
-import TileLayer from '../src/ol/layer/Tile.js';
 import OSM from '../src/ol/source/OSM.js';
-
+import TileLayer from '../src/ol/layer/Tile.js';
+import View from '../src/ol/View.js';
+import {Control, defaults as defaultControls} from '../src/ol/control.js';
 
 //
 // Define rotate to north control.
 //
 
 class RotateNorthControl extends Control {
-
   /**
    * @param {Object=} opt_options Control options.
    */
@@ -26,7 +24,7 @@ class RotateNorthControl extends Control {
 
     super({
       element: element,
-      target: options.target
+      target: options.target,
     });
 
     button.addEventListener('click', this.handleRotateNorth.bind(this), false);
@@ -35,28 +33,23 @@ class RotateNorthControl extends Control {
   handleRotateNorth() {
     this.getMap().getView().setRotation(0);
   }
-
 }
 
-
 //
 // Create map, giving it a rotate to north control.
 //
 
-
 const map = new Map({
-  controls: defaultControls().extend([
-    new RotateNorthControl()
-  ]),
+  controls: defaultControls().extend([new RotateNorthControl()]),
   layers: [
     new TileLayer({
-      source: new OSM()
-    })
+      source: new OSM(),
+    }),
   ],
   target: 'map',
   view: new View({
     center: [0, 0],
     zoom: 3,
-    rotation: 1
-  })
+    rotation: 1,
+  }),
 });