Add optional startup chime

Enable STARTUP_CHIME in Configuration.h to play a short chime on Trigorilla startup/serial connection, disabled by default

Marlin/AnycubicTFT.cpp

@@ -115,6 +115,13 @@ void AnycubicTFTClass::Setup() {
 
   SelectedDirectory[0]=0;
   SpecialMenu=false;
+
+  #ifdef STARTUP_CHIME
+    buzzer.tone(250, 554); // C#5
+    buzzer.tone(250, 740); // F#5
+    buzzer.tone(250, 554); // C#5
+    buzzer.tone(500, 831); // G#5
+  #endif
 }
 
 void AnycubicTFTClass::WriteOutageEEPromData() {

Marlin/Configuration.h

@@ -1518,6 +1518,14 @@
 //
 #define SPEAKER
 
+//
+// STARTUP CHIME
+//
+// Play a (non-earpiercing) startup chime on startup/serial connection
+// of the Trigorilla board
+//
+//#define STARTUP_CHIME
+
 //
 // The duration and frequency for the UI feedback sound.
 // Set these to 0 to disable audio feedback in the LCD menus.