Fix broken logo URL + replace old nonodes background

src/Umbraco.Cms.StaticAssets/umbraco/UmbracoWebsite/NoNodes.cshtml

@@ -26,7 +26,7 @@
         <article>
             <div>
                 <div class="logo" aria-hidden="true">
-                    <img alt="Umbraco" src="umbraco/assets/img/application/logo_white.svg" width="91" height="91" />
+                    <img alt="Umbraco" src="umbraco/backoffice/assets/umbraco_logomark_white.svg" width="91" height="91" />
                 </div>
 
                 <h1>Welcome to your Umbraco installation</h1>

src/Umbraco.Cms.StaticAssets/wwwroot/umbraco/website/nonodes.css

@@ -100,7 +100,7 @@ a, a:active, a:visited {
 }
 
 section {
-  background-image: url(/umbraco/website/nonodesbg.jpg);
+  background-image: url(/umbraco/website/nonodesbg.webp);
   background-position: 50%;
   background-size: cover;
   display: table;
@@ -149,11 +149,7 @@ section article > div {
 }
 
 section .logo {
-  background-image: url(/umbraco/website/logo.png);
-  background-repeat: no-repeat;
-  height: 91px;
   margin: 0 auto;
-  width: 91px;
 }
 
 section .row {