Fix USB MIDI: use Adafruit TinyUSB Library for proper MIDI support

- Add Adafruit TinyUSB Library dependency
- Create tusb_config.h enabling MIDI class
- USB device named 'Loopy Foot Controller'
- is_connected() check before sending

src/tusb_config.h

@@ -0,0 +1,21 @@
+#ifndef TUSB_CONFIG_H
+#define TUSB_CONFIG_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define CFG_TUD_MIDI 1
+#define CFG_TUD_MIDI_RX_BUFSIZE 64
+#define CFG_TUD_MIDI_TX_BUFSIZE 64
+
+#define CFG_TUD_CDC 0
+#define CFG_TUD_MSC 0
+#define CFG_TUD_HID 0
+#define CFG_TUD_NET 0
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif