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.

src/ol/format/JSONFeature.js

@@ -1,9 +1,9 @@
 /**
  * @module ol/format/JSONFeature
  */
-import {abstract} from '../util.js';
 import FeatureFormat from './Feature.js';
 import FormatType from './FormatType.js';
+import {abstract} from '../util.js';
 
 /**
  * @classdesc
@@ -36,7 +36,9 @@ class JSONFeature extends FeatureFormat {
    */
   readFeature(source, opt_options) {
     return this.readFeatureFromObject(
-      getObject(source), this.getReadOptions(source, opt_options));
+      getObject(source),
+      this.getReadOptions(source, opt_options)
+    );
   }
 
   /**
@@ -50,7 +52,9 @@ class JSONFeature extends FeatureFormat {
    */
   readFeatures(source, opt_options) {
     return this.readFeaturesFromObject(
-      getObject(source), this.getReadOptions(source, opt_options));
+      getObject(source),
+      this.getReadOptions(source, opt_options)
+    );
   }
 
   /**
@@ -85,7 +89,9 @@ class JSONFeature extends FeatureFormat {
    */
   readGeometry(source, opt_options) {
     return this.readGeometryFromObject(
-      getObject(source), this.getReadOptions(source, opt_options));
+      getObject(source),
+      this.getReadOptions(source, opt_options)
+    );
   }
 
   /**
@@ -187,7 +193,6 @@ class JSONFeature extends FeatureFormat {
   }
 }
 
-
 /**
  * @param {Document|Element|Object|string} source Source.
  * @return {Object} Object.
@@ -203,5 +208,4 @@ function getObject(source) {
   }
 }
 
-
 export default JSONFeature;