refactor: Add more checks to pre-commit

Updated existing pre-commit hooks and added some new hooks:

- Remove trailing whitespace
- Ensure every non-empty file ends with a new line
- Check YAML file validity
- Prevent adding large files
- Ensure any scripts with shebangs are executable

Added a GitHub action to run pre-commit on every commit. Removed any
existing actions which duplicate pre-commit.

Ran pre-commit on the codebase.

app/boards/shields/zmk_uno/zmk_uno.keymap

@@ -29,8 +29,8 @@
 };
 
 REMOVE ME: */
- 
- 
+
+
 / {
     macros {
         ZMK_MACRO(ble_zero,
@@ -47,7 +47,7 @@ REMOVE ME: */
 
     keymap {
         compatible = "zmk,keymap";
- 
+
         default_layer {
             bindings = <
                 &kp A &bl BL_TOG
@@ -55,7 +55,7 @@ REMOVE ME: */
 
                 &out OUT_USB &ble_zero &ble_one
            >;
-	
+
            sensor-bindings = <&inc_dec_kp C_VOL_UP C_VOL_DN>;
         };
     };