Review refinements.

- added docs for supported display configurations
- removed enforcement for DISPLAY_TYPE_NONE on esp boards

Author: andre-stefanov

Software/Arduino code/OpenAstroTracker/Configuration_adv.hpp

@@ -207,8 +207,6 @@
 //
 // Define some things, dont change: ///
 #define ESPBOARD
-#undef DISPLAY_TYPE
-#define DISPLAY_TYPE DISPLAY_TYPE_NONE
 // #define BLUETOOTH_ENABLED
 #define WIFI_ENABLED 
 #if defined(ESP8266) 

Software/Arduino code/OpenAstroTracker/Constants.hpp

@@ -1,22 +1,27 @@
 #pragma once
 
-/*
-* This file contains constants that SHOULD NOT BE CHANGED by oat users!
-* If you are a developer and want to add new hardware support, add a
-* proper definition here with increased value.
-*/
+/**
+ * This file contains constants that SHOULD NOT BE CHANGED by oat users!
+ * If you are a developer and want to add new hardware support, add a
+ * proper definition here with increased value.
+ **/
 
-// Supported display types
-#define DISPLAY_TYPE_NONE           0
-#define DISPLAY_TYPE_LCD_KEYPAD     1
+/**
+ * Supported display types. Use one of these values for DISPLAY_TYPE configuration matching your used display.
+ * 
+ * DISPLAY_TYPE_NONE:           No display. Use this if you don't use any display.
+ * DISPLAY_TYPE_LCD_KEYPAD:     1602 LCD Keypad shield which can be mounted directly to an Arduino UNO / Mega boards.
+ *                              Example: https://www.digikey.com/en/products/detail/dfrobot/DFR0009/7597118
+ **/
+#define DISPLAY_TYPE_NONE       0
+#define DISPLAY_TYPE_LCD_KEYPAD 1
 
 // Supported stepper models
-#define STEPPER_TYPE_28BYJ48  0
-#define STEPPER_TYPE_NEMA17   1
+#define STEPPER_TYPE_28BYJ48    0
+#define STEPPER_TYPE_NEMA17     1
 
 // Supported stepper driver models
-#define DRIVER_TYPE_ULN2003              0
-#define DRIVER_TYPE_GENERIC              1
-#define DRIVER_TYPE_TMC2209_STANDALONE   2
-#define DRIVER_TYPE_TMC2209_UART         3
-
+#define DRIVER_TYPE_ULN2003             0
+#define DRIVER_TYPE_GENERIC             1
+#define DRIVER_TYPE_TMC2209_STANDALONE  2
+#define DRIVER_TYPE_TMC2209_UART        3