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.

rendering/cases/layer-group/main.js

@@ -1,13 +1,13 @@
 import Map from '../../../src/ol/Map.js';
 import View from '../../../src/ol/View.js';
-import {Group as LayerGroup, Tile as TileLayer} from '../../../src/ol/layer.js';
 import XYZ from '../../../src/ol/source/XYZ.js';
+import {Group as LayerGroup, Tile as TileLayer} from '../../../src/ol/layer.js';
 
 new Map({
   target: 'map',
   view: new View({
     center: [0, 0],
-    zoom: 3
+    zoom: 3,
   }),
   layers: new LayerGroup({
     opacity: 0.75,
@@ -15,16 +15,16 @@ new Map({
       new TileLayer({
         opacity: 0.25,
         source: new XYZ({
-          url: '/data/tiles/satellite/{z}/{x}/{y}.jpg'
-        })
+          url: '/data/tiles/satellite/{z}/{x}/{y}.jpg',
+        }),
       }),
       new TileLayer({
         source: new XYZ({
-          url: '/data/tiles/stamen-labels/{z}/{x}/{y}.png'
-        })
-      })
-    ]
-  })
+          url: '/data/tiles/stamen-labels/{z}/{x}/{y}.png',
+        }),
+      }),
+    ],
+  }),
 });
 
 render();