[Keyboard] Add CMK11 (#23239)

* adding cmk11

* correcting default keymap

* removing rules.mk

* removing unnecessary comment

keyboards/custommk/cmk11/keymaps/default/keymap.c

@@ -0,0 +1,11 @@
+// Copyright 2024 customMK
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include QMK_KEYBOARD_H
+
+const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
+    [0] = LAYOUT(
+        KC_ESC,  KC_C,    KC_V,   KC_VOLU, KC_VOLD, KC_DEL,
+        KC_LCTL, KC_PGUP, KC_SPC, KC_PGDN, KC_ENT
+    )
+};