build: switch from yarn to npm to manage js dependencies and move js contents to root

yarn v1 is being deprecated and starts to have some issues

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

src/shims-tsx.d.ts

@@ -0,0 +1,11 @@
+import Vue, { VNode } from "vue";
+
+declare global {
+  namespace JSX {
+    interface Element extends VNode {}
+    interface ElementClass extends Vue {}
+    interface IntrinsicElements {
+      [elem: string]: any;
+    }
+  }
+}