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/xyz-esri.js

@@ -1,24 +1,25 @@
 import Map from '../src/ol/Map.js';
-import View from '../src/ol/View.js';
 import TileLayer from '../src/ol/layer/Tile.js';
-import {fromLonLat} from '../src/ol/proj.js';
+import View from '../src/ol/View.js';
 import XYZ from '../src/ol/source/XYZ.js';
-
+import {fromLonLat} from '../src/ol/proj.js';
 
 const map = new Map({
   target: 'map',
   layers: [
     new TileLayer({
       source: new XYZ({
-        attributions: 'Tiles © <a href="https://services.arcgisonline.com/ArcGIS/' +
-            'rest/services/World_Topo_Map/MapServer">ArcGIS</a>',
-        url: 'https://server.arcgisonline.com/ArcGIS/rest/services/' +
-            'World_Topo_Map/MapServer/tile/{z}/{y}/{x}'
-      })
-    })
+        attributions:
+          'Tiles © <a href="https://services.arcgisonline.com/ArcGIS/' +
+          'rest/services/World_Topo_Map/MapServer">ArcGIS</a>',
+        url:
+          'https://server.arcgisonline.com/ArcGIS/rest/services/' +
+          'World_Topo_Map/MapServer/tile/{z}/{y}/{x}',
+      }),
+    }),
   ],
   view: new View({
     center: fromLonLat([-121.1, 47.5]),
-    zoom: 7
-  })
+    zoom: 7,
+  }),
 });