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/arm/pillbug/pillbug.dts

@@ -29,7 +29,7 @@
             label = "Blue LED";
         };
     };
-    
+
     ext-power {
         compatible = "zmk,ext-power-generic";
         label = "EXT_POWER";