[FEATURE] Check if command exits

[CyberDudeJ]

Ensure the command being run by lp can indeed be run before it gets executed.

def command_exists(command):
    try:
        subprocess.check_output(['which', command])
        return True
    except subprocess.CalledProcessError:
        return False

# Example usage in a loop
while True:
    package_manager = find_package_manager()
    if package_manager:
        print(f"Found package manager: {package_manager}")
        break
    else:
        print("Waiting for a package manager to be available...")
        time.sleep(1)

Required Packages: subprocess