[Keyboard] Add support for XD004 macro keyboard (#6337)

* Add support for XD004

Also applying the following suggested edits:

Add hardware availability link in readme
Co-Authored-By: Drashna Jaelre <drashna@live.com>

Enable lite bootmagic
Co-Authored-By: Drashna Jaelre <drashna@live.com>

Remove commented out MCU
Co-Authored-By: fauxpark <fauxpark@gmail.com>

* Add more ellaborate keymap

Correcting usage of tap_code_16 for modified key, thanks to @drashna

* Add information about bootloader type

Co-Authored-By: Drashna Jaelre <drashna@live.com>

layouts/community/ortho_1x4/belgorath/keymap.c

@@ -0,0 +1,24 @@
+#include QMK_KEYBOARD_H
+
+extern keymap_config_t keymap_config;
+
+// Each layer gets a name for readability, which is then used in the keymap matrix below.
+// The underscores don't mean anything - you can have a layer called STUFF or any other name.
+// Layer names don't all need to be of the same length, obviously, and you can also skip them
+// entirely and just use numbers.
+
+#define _DEFAULT 0
+#define _LOWER  1
+#define LOWER  LT(_LOWER, KC_PENT)
+
+const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
+
+[_DEFAULT] = LAYOUT_ortho_1x4 (
+    LOWER,  KC_P0,  KC_PDOT,KC_PAST 
+),
+
+/* Lower */
+[_LOWER] = LAYOUT_ortho_1x4 ( 
+    _______,_______,_______,_______ 
+),
+};

layouts/community/ortho_1x4/layout.json

@@ -0,0 +1 @@
+["","","",""]