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/interaction/PinchRotate.js

@@ -1,11 +1,12 @@
 /**
  * @module ol/interaction/PinchRotate
  */
+import PointerInteraction, {
+  centroid as centroidFromPointers,
+} from './Pointer.js';
 import {FALSE} from '../functions.js';
-import PointerInteraction, {centroid as centroidFromPointers} from './Pointer.js';
 import {disable} from '../rotationconstraint.js';
 
-
 /**
  * @typedef {Object} Options
  * @property {number} [duration=250] The duration of the animation in
@@ -13,7 +14,6 @@ import {disable} from '../rotationconstraint.js';
  * @property {number} [threshold=0.3] Minimal angle in radians to start a rotation.
  */
 
-
 /**
  * @classdesc
  * Allows the user to rotate the map by twisting with two fingers
@@ -25,7 +25,6 @@ class PinchRotate extends PointerInteraction {
    * @param {Options=} opt_options Options.
    */
   constructor(opt_options) {
-
     const options = opt_options ? opt_options : {};
 
     const pointerOptions = /** @type {import("./Pointer.js").Options} */ (options);
@@ -71,7 +70,6 @@ class PinchRotate extends PointerInteraction {
      * @type {number}
      */
     this.duration_ = options.duration !== undefined ? options.duration : 250;
-
   }
 
   /**
@@ -87,13 +85,13 @@ class PinchRotate extends PointerInteraction {
     // angle between touches
     const angle = Math.atan2(
       touch1.clientY - touch0.clientY,
-      touch1.clientX - touch0.clientX);
+      touch1.clientX - touch0.clientX
+    );
 
     if (this.lastAngle_ !== undefined) {
       const delta = angle - this.lastAngle_;
       this.rotationDelta_ += delta;
-      if (!this.rotating_ &&
-          Math.abs(this.rotationDelta_) > this.threshold_) {
+      if (!this.rotating_ && Math.abs(this.rotationDelta_) > this.threshold_) {
         this.rotating_ = true;
       }
       rotationDelta = delta;