Ports a rewritten version of BAYSTRUMENTS (#11680)

* bay instruments

* k

* AAA

* remove that

* changes

* Update _instrument_key.dm

* safety nets

* @ghommie fixed

* volume

* Update item.dm

* Update item.dm

Co-authored-by: Ghom <42542238+Ghommie@users.noreply.github.com>

code/__DEFINES/instruments.dm

@@ -0,0 +1,29 @@
+#define INSTRUMENT_MIN_OCTAVE 1
+#define INSTRUMENT_MAX_OCTAVE 9
+#define INSTRUMENT_MIN_KEY 0
+#define INSTRUMENT_MAX_KEY 127
+
+/// Max number of playing notes per instrument.
+#define CHANNELS_PER_INSTRUMENT 128
+
+/// Distance multiplier that makes us not be impacted by 3d sound as much. This is a multiplier so lower it is the closer we will pretend to be to people.
+#define INSTRUMENT_DISTANCE_FALLOFF_BUFF 0.2
+/// How many tiles instruments have no falloff for
+#define INSTRUMENT_DISTANCE_NO_FALLOFF 3
+
+/// Maximum length a note should ever go for
+#define INSTRUMENT_MAX_TOTAL_SUSTAIN (5 SECONDS)
+
+/// These are per decisecond.
+#define INSTRUMENT_EXP_FALLOFF_MIN			1.025		//100/(1.025^50) calculated for [INSTRUMENT_MIN_SUSTAIN_DROPOFF] to be 30.
+#define INSTRUMENT_EXP_FALLOFF_MAX			10
+
+/// Minimum volume for when the sound is considered dead.
+#define INSTRUMENT_MIN_SUSTAIN_DROPOFF 30
+
+#define SUSTAIN_LINEAR 1
+#define SUSTAIN_EXPONENTIAL 2
+
+// /datum/instrument instrument_flags
+#define INSTRUMENT_LEGACY (1<<0)					//Legacy instrument. Implies INSTRUMENT_DO_NOT_AUTOSAMPLE
+#define INSTRUMENT_DO_NOT_AUTOSAMPLE (1<<1)			//Do not automatically sample