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/earthquake-custom-symbol.js

@@ -1,22 +1,29 @@
-import Map from '../src/ol/Map.js';
-import View from '../src/ol/View.js';
 import KML from '../src/ol/format/KML.js';
+import Map from '../src/ol/Map.js';
 import Polygon from '../src/ol/geom/Polygon.js';
-import {Tile as TileLayer, Vector as VectorLayer} from '../src/ol/layer.js';
-import {toContext} from '../src/ol/render.js';
 import Stamen from '../src/ol/source/Stamen.js';
 import VectorSource from '../src/ol/source/Vector.js';
+import View from '../src/ol/View.js';
 import {Fill, Icon, Stroke, Style} from '../src/ol/style.js';
+import {Tile as TileLayer, Vector as VectorLayer} from '../src/ol/layer.js';
+import {toContext} from '../src/ol/render.js';
 
-
-const symbol = [[0, 0], [4, 2], [6, 0], [10, 5], [6, 3], [4, 5], [0, 0]];
+const symbol = [
+  [0, 0],
+  [4, 2],
+  [6, 0],
+  [10, 5],
+  [6, 3],
+  [4, 5],
+  [0, 0],
+];
 let scale;
-const scaleFunction = function(coordinate) {
+const scaleFunction = function (coordinate) {
   return [coordinate[0] * scale, coordinate[1] * scale];
 };
 
 const styleCache = {};
-const styleFunction = function(feature) {
+const styleFunction = function (feature) {
   // 2012_Earthquakes_Mag5.kml stores the magnitude of each earthquake in a
   // standards-violating <magnitude> tag in each Placemark.  We extract it from
   // the Placemark's name instead.
@@ -27,19 +34,23 @@ const styleFunction = function(feature) {
   let style = styleCache[size];
   if (!style) {
     const canvas = document.createElement('canvas');
-    const vectorContext = toContext(canvas.getContext('2d'),
-      {size: [size, size], pixelRatio: 1});
-    vectorContext.setStyle(new Style({
-      fill: new Fill({color: 'rgba(255, 153, 0, 0.4)'}),
-      stroke: new Stroke({color: 'rgba(255, 204, 0, 0.2)', width: 2})
-    }));
+    const vectorContext = toContext(canvas.getContext('2d'), {
+      size: [size, size],
+      pixelRatio: 1,
+    });
+    vectorContext.setStyle(
+      new Style({
+        fill: new Fill({color: 'rgba(255, 153, 0, 0.4)'}),
+        stroke: new Stroke({color: 'rgba(255, 204, 0, 0.2)', width: 2}),
+      })
+    );
     vectorContext.drawGeometry(new Polygon([symbol.map(scaleFunction)]));
     style = new Style({
       image: new Icon({
         img: canvas,
         imgSize: [size, size],
-        rotation: 1.2
-      })
+        rotation: 1.2,
+      }),
     });
     styleCache[size] = style;
   }
@@ -50,16 +61,16 @@ const vector = new VectorLayer({
   source: new VectorSource({
     url: 'data/kml/2012_Earthquakes_Mag5.kml',
     format: new KML({
-      extractStyles: false
-    })
+      extractStyles: false,
+    }),
   }),
-  style: styleFunction
+  style: styleFunction,
 });
 
 const raster = new TileLayer({
   source: new Stamen({
-    layer: 'toner'
-  })
+    layer: 'toner',
+  }),
 });
 
 const map = new Map({
@@ -67,6 +78,6 @@ const map = new Map({
   target: 'map',
   view: new View({
     center: [0, 0],
-    zoom: 2
-  })
+    zoom: 2,
+  }),
 });