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/TileCache.js

@@ -5,7 +5,6 @@ import LRUCache from './structs/LRUCache.js';
 import {fromKey, getKey} from './tilecoord.js';
 
 class TileCache extends LRUCache {
-
   /**
    * @param {!Object<string, boolean>} usedTiles Used tiles.
    */
@@ -30,14 +29,15 @@ class TileCache extends LRUCache {
     const key = this.peekFirstKey();
     const tileCoord = fromKey(key);
     const z = tileCoord[0];
-    this.forEach(function(tile) {
-      if (tile.tileCoord[0] !== z) {
-        this.remove(getKey(tile.tileCoord));
-        tile.release();
-      }
-    }.bind(this));
+    this.forEach(
+      function (tile) {
+        if (tile.tileCoord[0] !== z) {
+          this.remove(getKey(tile.tileCoord));
+          tile.release();
+        }
+      }.bind(this)
+    );
   }
 }
 
-
 export default TileCache;