Remove invariant code from Configurations

- Add `Conditionals.h` with calculated configuration values
- Add `SanityCheck.h` with checks for configuration errors
- Remove equivalent code from all configurations
- Move error checks from some sources to `SanityCheck.h` also
- Fix initialization of count_direction in stepper.cpp

Marlin/ultralcd.cpp

@@ -1189,10 +1189,6 @@ void lcd_init() {
      WRITE(SHIFT_OUT,HIGH);
      WRITE(SHIFT_LD,HIGH);
      WRITE(SHIFT_EN,LOW);
-  #else
-     #ifdef ULTIPANEL
-     #error ULTIPANEL requires an encoder
-     #endif
   #endif // SR_LCD_2W_NL
 #endif//!NEWPANEL