Add delay and spinner for station map, common const and component for delay

web/src/components/LoadingSpinner.tsx

@@ -0,0 +1,10 @@
+import { Component } from "solid-js";
+
+export const LoadingSpinner: Component<{ text: string; }> = ({ text }) => {
+    return (
+        <div>
+            <span class="spinner"></span>
+            <span style={{ "padding-left": "16px" }}>{ text }</span>
+        </div>
+    );
+}