(#13542) Add more YARD and fix a typo

This patch corrects existing and adds additional YARD and fixes
a typo in a variable name.
(#13542) Embed and use Arachive::Tar::Minitar

This patch embeds the minitar gem into puppet while changing its namespace to:
  Puppet::Util::Archive::Tar::Minitar
and makes use of it instead of the previously used rubygems tar code.
The patch also makes sure that the data structure produced by the installer &
upgrader applications is backward compatible (i.e. it contains all the fields
the original structure used to contain in addition to several new ones).
(#13542) Update unit tests broken by the PMT install code changes

This patch updates/removes unit tests broken by the PMT install/upgrade
changes.