Add long descriptions to some plugins

Edited the short descriptions to answer the question
"What can I do with this extension" to help users decide
whether they need it.

In long descriptions, tell users what else they need to
be able to use the plugin.

Change-Id: Iefce7505b61fc77cf38cc915f1f7dbd25c9cb570
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/ios/Ios.json.in

@@ -14,7 +14,13 @@
                   "Alternatively, this plugin may be used under the terms of the GNU General Public License version 3 as published by the Free Software Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT included in the packaging of this plugin. Please review the following information to ensure the GNU General Public License requirements will be met: https://www.gnu.org/licenses/gpl-3.0.html."
     ],
     "Category" : "Device Support",
-    "Description" : "Support for deployment to and execution on iOS Devices.",
+    "Description" : "Develop applications for iOS devices",
+    "LongDescription" : [
+        "Connect devices with USB or use the iOS simulator to run, debug, and analyze applications built for iOS.",
+        "You also need:",
+            "- Qt for iOS",
+            "- Xcode"
+    ],
     "Url" : "https://www.qt.io",
     ${IDE_PLUGIN_DEPENDENCIES}
 }