added open service logs to logs page (#951)

* added open service logs to logs page
* redesign of log saving buttons
* hide service logs buttons for mobile platforms
* refactoring: moved logger to common folder
* feature: added the ability to enable logs to the start screen

client/ui/qml/Pages2/PageStart.qml

@@ -202,6 +202,14 @@ PageType {
             PageController.showNotificationMessage(qsTr("Settings restored from backup file"))
             PageController.goToPageHome()
         }
+
+        function onLoggingStateChanged() {
+            if (SettingsController.isLoggingEnabled) {
+                var message = qsTr("Logging is enabled. Note that logs will be automatically" +
+                                   "disabled after 14 days, and all log files will be deleted.")
+                PageController.showNotificationMessage(message)
+            }
+        }
     }
 
     StackViewType {