[Keyboard] Add SkeletonNumPad (#16753)

* add SkeletonNumPad keyboard

* fix

* fix

* fixed info.json

* Update keyboards/skeletonkbd/skeletonnumpad/rules.mk

Co-authored-by: Ryan <fauxpark@gmail.com>

* Change RGBLIGHT_LIMIT_VAL

Co-authored-by: Ryan <fauxpark@gmail.com>

keyboards/skeletonkbd/skeletonnumpad/rules.mk

@@ -0,0 +1,18 @@
+# MCU name
+MCU = atmega32u4
+
+# Bootloader selection
+BOOTLOADER = atmel-dfu
+
+# Build Options
+#   change yes to no to disable
+#
+BOOTMAGIC_ENABLE = yes      # Enable Bootmagic Lite
+MOUSEKEY_ENABLE = yes       # Mouse keys
+EXTRAKEY_ENABLE = yes       # Audio control and System control
+CONSOLE_ENABLE = no         # Console for debug
+COMMAND_ENABLE = no         # Commands for debug and configuration
+NKRO_ENABLE = no            # Enable N-Key Rollover
+BACKLIGHT_ENABLE = no       # Enable keyboard backlight functionality
+RGBLIGHT_ENABLE = yes       # Enable keyboard RGB underglow
+AUDIO_ENABLE = no           # Audio output