Delete output directory if an error occurred

[aniruddha2000]

Goals
In case that an error occurs, the user should know what went wrong. For this, he expects a good error message. Other than that the output directory which might already contain some of the generated files, should be deleted.

Otherwise, the user might think that the cluster stack release is usable, even though it is not. Additionally, we have to overwrite the directory anyway in case of a stable or beta release. This should not be necessary if the previous run fails.

/kind proposal