[Keyboard] Add Axostudio Yeti hotswap version (#16820)

Co-authored-by: Joel Challis <git@zvecr.com>
Co-authored-by: Ryan <fauxpark@gmail.com>

keyboards/axolstudio/yeti/hotswap/readme.md

@@ -0,0 +1,27 @@
+# Axolstudio Yeti RGB
+
+![yeti](https://i.imgur.com/eoRH6W1l.png)
+
+**TGR Alice inspired board with some extra heft**
+
+* Keyboard Maintainer: [kb-elmo](https://github.com/kb-elmo)
+* Hardware Supported: Axolstudio Yeti Hotswap RGB PCB
+* Hardware Availability: https://axolstudio.ca/yeti
+
+Make example for this keyboard (after setting up your build environment):
+
+    make axolstudio/yeti/hotswap:default
+
+Flashing example for this keyboard:
+
+    make axolstudio/yeti/hotswap: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