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/uri.js

@@ -2,7 +2,6 @@
  * @module ol/uri
  */
 
-
 /**
  * Appends query parameters to a URI.
  *
@@ -14,7 +13,7 @@
 export function appendParams(uri, params) {
   const keyParams = [];
   // Skip any null or undefined parameter values
-  Object.keys(params).forEach(function(k) {
+  Object.keys(params).forEach(function (k) {
     if (params[k] !== null && params[k] !== undefined) {
       keyParams.push(k + '=' + encodeURIComponent(params[k]));
     }