Showcase refactor (#20)

* refactor: update voice.js

* refactor: update fallback.js

* refactor: update music.js

* refactor: update player.js

* refactor: misc changes

* feat: added background.js

* feat: added logo.js

* chore: update

* refactor: port all changes

* fix: fix WE issues

* fix: code cleanup

showcase/src/components/aklive2d.css

@@ -0,0 +1,8 @@
+#settings-box {
+    position: fixed;
+    left: 0;
+    top: 0;
+    background-color: white;
+    user-select: auto;
+    z-index: 999;
+}