Add path prepending support

[distroJack]

Current archive provider can only mirror file structures that appear on the host system when creating archives.

I propose adding a prepended_path attribute to the provider. This would prefix the path within the generated archive. Only archives generated using source_dir and source_file attributes would be prepended so that all files within the archive would be found a prepended_path/{source_dir/source_file}.

This will be especially useful (to me) when using the archive provider to upload aws lambda layers.

[hashicorp-cla]

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