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/mapbox-style.js

@@ -1,6 +1,9 @@
-import apply from 'ol-mapbox-style';
 import FullScreen from '../src/ol/control/FullScreen.js';
+import apply from 'ol-mapbox-style';
 
-apply('map', 'https://api.maptiler.com/maps/topo/style.json?key=get_your_own_D6rA4zTHduk6KOKTXzGB').then(function(map) {
+apply(
+  'map',
+  'https://api.maptiler.com/maps/topo/style.json?key=get_your_own_D6rA4zTHduk6KOKTXzGB'
+).then(function (map) {
   map.addControl(new FullScreen());
 });