[Keymap] Add new snailmap keymap to nullbitsco/nibble keyboard (#14024)

Co-authored-by: Ryan <[email protected]>

keyboards/nullbitsco/nibble/keymaps/snailmap/readme.md

@@ -0,0 +1,36 @@
+
+# SnailMap
+
+![KeySnail](https://i.imgur.com/yEQJyI2h.png)
+
+## :snail: Display
+
+- Mini keyboard that highlights the currently pressed keys
+- Snail icon that changes based on the current WPM
+- Current and max WPM counters
+- Active layer name
+- WPM graph
+
+## :gear: Customization
+
+The `OLED configuration variables` can be used to easily customize the display
+
+```
+oled_horizontal     - Horizontal or vertical orientation
+ansi_layout         - ANSI or ISO layout
+split_space         - Bottom row spacebar
+three_mods_left     - Left modifier keys
+three_mods_right    - Right modifier keys
+graph_direction     - Graph movement direction
+graph_refresh       - Frequency of graph lines
+graph_top_wpm       - WPM required to reach the top of the graph
+icon_med_wpm        - WPM required to display the medium snail
+icon_fast_wpm       - WPM required to display the fast snail
+MA_LAYER_NAME       - Layer 0 display name
+L1_LAYER_NAME       - Layer 1 display name
+L2_LAYER_NAME       - Layer 2 display name
+L3_LAYER_NAME       - Layer 3 display name
+```
+___
+
+###### *Keymap created by* [dogspace](https://github.com/dogspace)