Move buzzing code to buzzr.h & buzzer.cpp (PR#2307)

at least the lcd independent part from Marlin_main.cpp.

Marlin/buzzer.cpp

@@ -0,0 +1,22 @@
+#include "Marlin.h"
+#include "buzzer.h"
+#include "ultralcd.h"
+
+#if HAS_BUZZER
+  void buzz(long duration, uint16_t freq) {
+    if (freq > 0) {
+      #ifdef LCD_USE_I2C_BUZZER
+        lcd_buzz(duration, freq);
+      #elif defined(BEEPER) && BEEPER >= 0 // on-board buzzers have no further condition
+        SET_OUTPUT(BEEPER);
+        tone(BEEPER, freq, duration);
+        delay(duration);
+      #else
+        delay(duration);
+      #endif
+    }
+    else {
+      delay(duration);
+    }
+  }
+#endif