[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/readme.md

@@ -0,0 +1,27 @@
+# SkeletonNumPad
+
+![skeletonnumpad](https://i.imgur.com/nWPda21h.jpeg)
+
+Simple NumPad with acrylic case.
+
+-   Keyboard Maintainer: [SkeletonKBD](https://github.com/skeletonkbd/SkeletonNumPad)
+-   Hardware Supported: SkeletonNumPad
+-   Hardware Availability: https://github.com/skeletonkbd/SkeletonNumPad
+
+Make example for this keyboard (after setting up your build environment):
+
+    make skeletonkbd/skeletonnumpad:default
+
+Flashing example for this keyboard:
+
+    make skeletonkbd/skeletonnumpad:default:flash
+
+See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).
+
+## Bootloader
+
+Enter the bootloader in 3 ways:
+
+-   **Bootmagic reset**: Hold down the key at (0,0) in the matrix (usually the top left key or Escape) and plug in the keyboard
+-   **Physical reset button**: Briefly press the button on the back of the PCB - some may have pads you must short instead
+-   **Keycode in layout**: Press the key mapped to `RESET` if it is available