[Keyboard] Cleanup zhou65 and add nz64 keyboard (#17032)

Co-authored-by: Drashna Jaelre <drashna@live.com>

keyboards/yandrstudio/nz64/readme.md

@@ -0,0 +1,22 @@
+# nz64
+
+A 64 keys keyboard with rgb (keys).
+This keyboard use 16mhz HSE and STM32F401 as MCU.
+
+- Keyboard Maintainer: https://github.com/jiaxin96
+- Hardware Supported: nz64
+- Hardware Availability: https://github.com/Oh-My-Mechanical-Keyboard 
+
+Make example for this keyboard (after setting up your build environment):
+
+    make yandrstudio/nz64:default
+
+See [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) then the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information.
+
+## Bootloader
+
+Enter the bootloader in 3 ways:
+
+* **Bootmagic reset**: Hold down the key at (0,0) in the matrix (usually the top left key which is Escape in this keyboard) and plug in the keyboard
+* **Physical reset pins**: Short circuit the `bt0` and `vcc` pins on the back of the PCB and plug in the keyboard
+* **Keycode in layout**: Press the key mapped to `RESET` if it is available.