Adding support for Chatter keypad (#4022)

* Adding support for Chatter keypad

* Remove user button mapping since full keypad is now useable

* Adding TAB key and RIGHT to allow selecting a destination

* Fix shift bug (there's only three levels, not four)

* reformat file

* Fix bug with fast repeated keypresses

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Co-authored-by: Ben Meadors <benmmeadors@gmail.com>

src/input/SerialKeyboardImpl.h

@@ -0,0 +1,19 @@
+#pragma once
+#include "SerialKeyboard.h"
+#include "main.h"
+
+/**
+ * @brief The idea behind this class to have static methods for the event handlers.
+ *      Check attachInterrupt() at RotaryEncoderInteruptBase.cpp
+ *      Technically you can have as many rotary encoders hardver attached
+ *      to your device as you wish, but you always need to have separate event
+ *      handlers, thus you need to have a RotaryEncoderInterrupt implementation.
+ */
+class SerialKeyboardImpl : public SerialKeyboard
+{
+  public:
+    SerialKeyboardImpl();
+    void init();
+};
+
+extern SerialKeyboardImpl *aSerialKeyboardImpl;