Revamped how volume changes are handled to also support remote volume control

software/main/include/twai.h

@@ -2,5 +2,6 @@
 
 namespace twai {
 	void init();
+	void change_volume(bool up);
 }
 

software/main/include/volume.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <cstdint>
+#include <sys/lock.h>
+
+namespace volume_controller {
+	void init();
+	void set_from_radio(int volume);
+	void set_from_remote(int volume);
+
+	uint8_t current();
+}