split keyboard input logic into platform specific code

src/tabcontrollers/KeyboardInput.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <vector>
+#include <QString>
+
+// application namespace
+namespace advsettings {
+
+class AudioTabController;
+
+class KeyboardInput
+{
+public:
+    virtual ~KeyboardInput() {};
+
+    virtual void sendKeyboardInput(QString input) = 0;
+    virtual void sendKeyboardEnter() = 0;
+    virtual void sendKeyboardBackspace(int count) = 0;
+};
+
+}
+