Implement clean before unpack

[damacus]

:person_frowning: Problem Statement

clean_up_before_unpack: when set to true, the content of the directory defined by path is deleted before to unpack the archive (and only if an unpack operation will be performed). This is useful to ensure a clean directory content after ark execution when the remote archive has been updated since previous chef-client run whereas its version is left unchanged.

:grey_question: Possible Solution

#112

:arrow_heading_up: Describe alternatives you've considered

Merging #112, however we're looking at reworking the cookbook and the code needs heavily rebasing.