Installer: Add Cache-Control header to static assets

This fixes UX where Launcher iframe blanks when navigating in the app

Change-Id: I2966ef383c77d2986b6892f3828581b7785e90b0
diff --git a/core/installer/welcome/appmanager-tmpl/base.html b/core/installer/welcome/appmanager-tmpl/base.html
index e119c0f..1cd8c3c 100644
--- a/core/installer/welcome/appmanager-tmpl/base.html
+++ b/core/installer/welcome/appmanager-tmpl/base.html
@@ -3,7 +3,7 @@
 	<head>
 		<meta charset="utf-8" />
         <link rel="stylesheet" href="/static/pico.2.0.6.min.css">
-        <link rel="stylesheet" type="text/css" href="/static/appmanager.css">
+        <link rel="stylesheet" type="text/css" href="/static/appmanager.css?v=0.0.1">
 		<meta name="viewport" content="width=device-width, initial-scale=1" />
 	</head>
 	<body>
@@ -26,6 +26,6 @@
 			  {{ block "content" . }}{{ end }}
 		  </div>
       </main>
-    <script src="/static/app-manager.js"></script>
+    <script src="/static/app-manager.js?v=0.0.1"></script>
 	</body>
 </html>