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.

src/ol/layer/VectorImage.js

@@ -2,8 +2,8 @@
  * @module ol/layer/VectorImage
  */
 import BaseVectorLayer from './BaseVector.js';
-import {assign} from '../obj.js';
 import CanvasVectorImageLayerRenderer from '../renderer/canvas/VectorImageLayer.js';
+import {assign} from '../obj.js';
 
 /**
  * @typedef {Object} Options
@@ -50,7 +50,6 @@ import CanvasVectorImageLayerRenderer from '../renderer/canvas/VectorImageLayer.
  * viewport extent. A larger ratio avoids cut images during panning, but will cause a decrease in performance.
  */
 
-
 /**
  * @classdesc
  * Vector data that is rendered client-side.
@@ -75,8 +74,8 @@ class VectorImageLayer extends BaseVectorLayer {
      * @type {number}
      * @private
      */
-    this.imageRatio_ = options.imageRatio !== undefined ? options.imageRatio : 1;
-
+    this.imageRatio_ =
+      options.imageRatio !== undefined ? options.imageRatio : 1;
   }
 
   /**
@@ -96,5 +95,4 @@ class VectorImageLayer extends BaseVectorLayer {
   }
 }
 
-
 export default VectorImageLayer;