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/size.js

@@ -2,14 +2,12 @@
  * @module ol/size
  */
 
-
 /**
  * An array of numbers representing a size: `[width, height]`.
  * @typedef {Array<number>} Size
  * @api
  */
 
-
 /**
  * Returns a buffered size.
  * @param {Size} size Size.
@@ -26,7 +24,6 @@ export function buffer(size, num, opt_size) {
   return opt_size;
 }
 
-
 /**
  * Determines if a size has a positive area.
  * @param {Size} size The size to test.
@@ -36,7 +33,6 @@ export function hasArea(size) {
   return size[0] > 0 && size[1] > 0;
 }
 
-
 /**
  * Returns a size scaled by a ratio. The result will be an array of integers.
  * @param {Size} size Size.
@@ -53,7 +49,6 @@ export function scale(size, ratio, opt_size) {
   return opt_size;
 }
 
-
 /**
  * Returns an `Size` array for the passed in number (meaning: square) or
  * `Size` array.