Add option to delete product folders after archiving

[laeubi]

Products can take up considerable amounts of space on the harddisk (e.g. CIs / local clones) as they are currently effectively there twice

1. A product is materialized into folders
2. A product is usually packed afterwards (e.g. zip, tar.gz, ...)

Beside that this is also duplicated for each build environment.

It would therefore be useful to have an option for the archive-products to delete the folder contents once after the packaging succeeds.