Rework buzzing (PR#2296)

by:
Moving HAS_LCD_BUZZ macro to Coditionals.h
Renaming HAS_LCD_BUZZ to HAS_BUZZER to make clear is has nothing to do with the lcd.
Removing the ULTRALCD condition.

Moving declaration of lcd_buzz() out of the ULTRA_LCD block in ultralcd.h
Moving definition of lcd_buzz() out of the ULTIPANEL block in ultralcd.cpp
Renaming lcd_buzz() to buzz() to make clear is has nothing to do with the lcd.

All buzzing code is now only dependent on the existence of a BEEPER-pin or the definition of a LCD_USE_I2C_BUZZER.

To do: Check the conditions for the BEEPER-pin in all pin-files.