Add unit testing support with vitest (#18)

* update loose files and add vitest

* update test scripts

* more support for vitest

* more test support

* update vscode settings

src/test/phaser.setup.ts

@@ -0,0 +1,5 @@
+import Phaser from "phaser";
+
+export default new Phaser.Game({
+  type: Phaser.HEADLESS,
+});

src/test/vitest.setup.ts

@@ -0,0 +1,2 @@
+import "vitest-canvas-mock";
+import "#app/test/phaser.setup";