Add helix keyboard (#2308)

* Fork from Let's Split

* Organizing files

* Delete some keymaps

* I2C and serial enabled at the same time

* Change readme

* add #define HELIX_ROWS for multiple rows

* Delete avrdude flashing script

* Delete makefiles

* Subproject elimination

* Fix lufa path

* Remove PLAY_NOTE_ARRAY usages to get rid of warning.

Fix conflicting function name

* Mousekey change default to off

* Fix to oled display adjust

* make rev2

change pin assign
change keymap

* use master_buffer

* Timing adjustment

* Organizing files

* Change Keymap

* Change Keymap

Add EISU and KANA
Correct 4rows

* NKRO default to disable

* EXTRAKEY_ENABLE default to disable

* add rgb reset key

* rgb custom function enable

*  Extend font

* add RGBLED_POWER

default folder to helix/rev2
RGB_ENABLE to no

* renamed directory

* Disable RGBLIGHT_CUSTOM_DRIVER

* Disable LOCKING_SUPPORT_ENABLE

* Update bootloader setting

* Change readme

* Fixed argument error

keyboards/helix/rev1/rev1.c

@@ -0,0 +1,39 @@
+#include "helix.h"
+
+#ifdef AUDIO_ENABLE
+    float tone_startup[][2] = SONG(STARTUP_SOUND);
+    float tone_goodbye[][2] = SONG(GOODBYE_SOUND);
+#endif
+
+#ifdef SSD1306OLED
+void led_set_kb(uint8_t usb_led) {
+    // put your keyboard LED indicator (ex: Caps Lock LED) toggling code here
+    led_set_user(usb_led);
+}
+#endif
+
+void matrix_init_kb(void) {
+
+    #ifdef AUDIO_ENABLE
+        _delay_ms(20); // gets rid of tick
+        PLAY_SONG(tone_startup);
+    #endif
+
+    // // green led on
+    // DDRD |= (1<<5);
+    // PORTD &= ~(1<<5);
+
+    // // orange led on
+    // DDRB |= (1<<0);
+    // PORTB &= ~(1<<0);
+
+	matrix_init_user();
+};
+
+void shutdown_kb(void) {
+    #ifdef AUDIO_ENABLE
+        PLAY_SONG(tone_goodbye);
+	_delay_ms(150);
+	stop_all_notes();
+    #endif
+}