start internationalization for addon description

src/_locales/de/messages.json

@@ -0,0 +1,10 @@
+{
+    "extensionName": {
+        "message": "Facebook Container",
+        "description": "Name of the extension."
+    },
+    "extensionDescription": {
+        "message": "Der Facebook-Container isoliert Ihre Facebook-Aktivitäten von den restlichen Webaktivitäten, um zu verhindern, dass Facebook Sie durch Cookies von Drittanbietern außerhalb der Website verfolgt.",
+        "description": "Description of the extension."
+    }
+}

src/_locales/en/messages.json

@@ -0,0 +1,10 @@
+{
+    "extensionName": {
+        "message": "Facebook Container",
+        "description": "Name of the extension."
+    },
+    "extensionDescription": {
+        "message": "Facebook Container isolates your Facebook activity from the rest of your web activity in order to prevent Facebook from tracking you outside of the Facebook website via third party cookies.",
+        "description": "Description of the extension."
+    }
+}

src/_locales/fr/messages.json

@@ -0,0 +1,10 @@
+{
+    "extensionName": {
+        "message": "Facebook Container",
+        "description": "Name of the extension."
+    },
+    "extensionDescription": {
+        "message": "Le conteneur Facebook isole votre activité Facebook du reste de votre activité Web afin d'empêcher Facebook de vous suivre en dehors de son site via des cookies tiers.",
+        "description": "Description of the extension."
+    }
+}

src/manifest.json

@@ -1,9 +1,11 @@
 {
     "manifest_version": 2,
-    "name": "Facebook Container",
+    "name": "__MSG_extensionName__",
     "version": "1.4.2",
 
-    "description": "Facebook Container isolates your Facebook activity from the rest of your web activity in order to prevent Facebook from tracking you outside of the Facebook website via third party cookies.",
+    "default_locale": "en",
+
+    "description": "__MSG_extensionDescription__",
 
     "icons": {
         "48": "icon.svg",