This PR changes the behavior of the command when you were specify a directory
instead of a filename, if the directory exists it would have deleted the
directory and the files in it.
The new flow and validation is now safer, if you specify a directory
Logstash will tell you to specify a complete filename.
If the ZIP extension is missing, the command line will ask you to make
sure you target a right filename.
If the output file already exist it will *not* delete it but instead
will return a warning message, you can force a delete by using the
`--overwrite` option.
Fixes: #6862Fixes#6861
