- add flag images for language switcher

- hide messages if room parameter is not given

assets/de.svg

@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 900 600">
+  <rect width="900" height="200" fill="#000"/>
+  <rect y="200" width="900" height="200" fill="#DD0000"/>
+  <rect y="400" width="900" height="200" fill="#FFCE00"/>
+</svg>

assets/fr.svg

@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 900 600">
+  <rect width="300" height="600" fill="#0055A4"/>
+  <rect x="300" width="300" height="600" fill="#fff"/>
+  <rect x="600" width="300" height="600" fill="#EF4135"/>
+</svg>

assets/uk.svg

@@ -0,0 +1,10 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 60 30">
+  <clipPath id="t">
+    <path d="M30,15 h30 v15 z v15 h-30 z h-30 v-15 z v-15 h30 z"/>
+  </clipPath>
+  <path d="M0,0 v30 h60 v-30 z" fill="#012169"/>
+  <path d="M0,0 L60,30 M60,0 L0,30" stroke="#fff" stroke-width="6"/>
+  <path d="M0,0 L60,30 M60,0 L0,30" clip-path="url(#t)" stroke="#C8102E" stroke-width="4"/>
+  <path d="M30,0 v30 M0,15 h60" stroke="#fff" stroke-width="10"/>
+  <path d="M30,0 v30 M0,15 h60" stroke="#C8102E" stroke-width="6"/>
+</svg>