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.

test/spec/ol/source/stamen.test.js

@@ -1,27 +1,21 @@
 import Stamen from '../../../../src/ol/source/Stamen.js';
 
-
-describe('ol.source.Stamen', function() {
-
-  describe('constructor', function() {
-
-    it('can be constructed with a custom minZoom', function() {
+describe('ol.source.Stamen', function () {
+  describe('constructor', function () {
+    it('can be constructed with a custom minZoom', function () {
       const source = new Stamen({
         layer: 'watercolor',
-        minZoom: 10
+        minZoom: 10,
       });
       expect(source.getTileGrid().getMinZoom()).to.be(10);
     });
 
-    it('can be constructed with a custom maxZoom', function() {
+    it('can be constructed with a custom maxZoom', function () {
       const source = new Stamen({
         layer: 'watercolor',
-        maxZoom: 8
+        maxZoom: 8,
       });
       expect(source.getTileGrid().getMaxZoom()).to.be(8);
-
     });
-
   });
-
 });