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/iris/Kconfig.defconfig

@@ -15,5 +15,5 @@ if SHIELD_IRIS_LEFT || SHIELD_IRIS_RIGHT
 
 config ZMK_SPLIT
 	default y
-	
+
 endif

app/boards/shields/iris/iris.dtsi

@@ -42,6 +42,6 @@ RC(3,0) RC(3,1) RC(3,2) RC(3,3) RC(3,4) RC(3,5) RC(4,2) RC(4,9) RC(3,6) RC(3,7)
 			, <&pro_micro 0 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>
 			, <&pro_micro 4 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>
 			;
-		
+
 	};
 };