[Keyboard] Add glacier in creatkeebs folder (#16079)

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

keyboards/creatkeebs/glacier/readme.md

@@ -0,0 +1,27 @@
+# glacier
+A 80% keyboard
+
+![glacier](https://i.imgur.com/BeyreN1.png)
+
+### Features
+* PCB gasket
+* Nickel-cobalt weight
+
+### Additional Information
+* Keyboard Maintainer: [Tim](https://github.com/Timliuzhaolu/qmk_firmware)
+* Hardware Supported: glacier PCB
+* Hardware Availability: [ESCHIT.com](https://eschit.com/products/gb-thera75)
+
+### Entering Bootloader
+
+Enter the bootloader in 2 ways:
+
+* Physical reset button: Press the `RESET` button on the back of the PCB.
+* Keycode in layout: Press the key mapped to `RESET` if it is available.
+
+### Building the Firmware
+Make example for this keyboard (after setting up your build environment):
+
+    make creatkeebs/glacier:default
+
+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).