Add some OpenGraph meta properties for prettier linking

web/index.html

@@ -2,6 +2,14 @@
 <script type="module" src="/src/sipgator-app.ts"></script>
 <meta charset="UTF-8">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
+<meta name="image" property="og:image" content="https://fumix.github.io/sipgator-open/favicon-banner.png">
+<meta property="og:image:type" content="image/png">
+<meta property="og:image:alt" content="Sipgator Open">
+<meta property="og:image:width" content="1200">
+<meta property="og:image:alt" content="630">
+<meta property="og:locale" content="de_DE">
+<meta property="og:type" content="website">
+<meta property="og:url" content="https://fumix.github.io/sipgator-open">
 <link rel="icon" type="image/xml+svg" href="./favicon.svg">
 <link rel="manifest" href="./app.webmanifest">
 <title>Sipgator</title>
@@ -51,7 +59,7 @@
   --on-primary-container:#2c1700;
   --secondary:#725a42;
   --on-secondary:#ffffff;
-  --secondary-container:#feddbe;
+  --secondary-container: #e6cdb4;
   --on-secondary-container:#291805;
   --tertiary:#57633b;
   --on-tertiary:#ffffff;