replace unsplash with kaya_bg

ref #17

src/Login.svelte

@@ -3,6 +3,7 @@
   import isUUID from "validator/lib/isUUID";
   import { apikey, lang, stationinfo, api_endpoint } from "./store.js";
   import axios from "axios";
+  import background from "./kaya_kids_background.jpg";
   import { _, locale } from "svelte-i18n";
   let token;
   let api_endpoint_input = "";
@@ -239,7 +240,7 @@
     <img
       alt=""
       class="object-cover w-full h-screen hidden md:block"
-      src="https://source.unsplash.com/IXUM4cJynP0"
+      src={background}
     />
   </div>
 </div>