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/arcgis-image.js

@@ -1,28 +1,29 @@
 import Map from '../src/ol/Map.js';
 import View from '../src/ol/View.js';
-import {Tile as TileLayer, Image as ImageLayer} from '../src/ol/layer.js';
-import {OSM, ImageArcGISRest} from '../src/ol/source.js';
+import {ImageArcGISRest, OSM} from '../src/ol/source.js';
+import {Image as ImageLayer, Tile as TileLayer} from '../src/ol/layer.js';
 
-const url = 'https://sampleserver1.arcgisonline.com/ArcGIS/rest/services/' +
-    'Specialty/ESRI_StateCityHighway_USA/MapServer';
+const url =
+  'https://sampleserver1.arcgisonline.com/ArcGIS/rest/services/' +
+  'Specialty/ESRI_StateCityHighway_USA/MapServer';
 
 const layers = [
   new TileLayer({
-    source: new OSM()
+    source: new OSM(),
   }),
   new ImageLayer({
     source: new ImageArcGISRest({
       ratio: 1,
       params: {},
-      url: url
-    })
-  })
+      url: url,
+    }),
+  }),
 ];
 const map = new Map({
   layers: layers,
   target: 'map',
   view: new View({
     center: [-10997148, 4569099],
-    zoom: 4
-  })
+    zoom: 4,
+  }),
 });