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/functions.js

@@ -47,7 +47,7 @@ export function memoizeOne(fn) {
 
   let lastThis;
 
-  return function() {
+  return function () {
     const nextArgs = Array.prototype.slice.call(arguments);
     if (!called || this !== lastThis || !arrayEquals(nextArgs, lastArgs)) {
       called = true;