[Keyboard] Add nullbitsco SCRAMBLE (#11078)

* Add SCRAMBLE

* Make requested changes to PR

* Add all layers to VIA keymap

Implement drashna's PR feedback in order to avoid random data within the layers in VIA.

* Make requested changes to PR

Implement fauxpark's PR feedback to clean up readme.md and rules.mk.

* Make changes based on PR feedback

-Changed VIA layers to enum
-Added info on how to enter the bootloader to readme

keyboards/nullbitsco/scramble/keymaps/default/keymap.c

@@ -0,0 +1,41 @@
+/*
+Copyright 2020 Jay Greco
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include QMK_KEYBOARD_H
+
+#define _BASE 1
+
+const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
+
+[_BASE] = LAYOUT(
+    KC_F13, KC_F14, KC_F15,
+    KC_F16, KC_F17, KC_F18
+)
+
+};
+
+void matrix_init_user(void) {
+  set_scramble_LED(LED_OFF);
+}
+
+void encoder_update_user(uint8_t index, bool clockwise) {
+    if (clockwise) {
+        tap_code(KC_VOLU);
+    } else {
+        tap_code(KC_VOLD);
+    }
+}