(QENG-989,990) Clean up open source install rough edges

This ensures that puppet and friends are available after gem installs on
Solaris and Debian. It also makes sure that the config directory and
hiera.yaml file are aways present. The former change fixes QENG-989 while
the latter fixes QENG-990).
Should this be accompanied by a corresponding removal of https://github.com/puppetlabs/beaker/blob/master/lib/beaker/host/unix.rb#L50? This seems like a good solution of this is the only place hiera.yaml is used or is expected to be used in the future, otherwise I'd consider defining the `hiera*` per-host options for in the windows host type as mentioned in QENG-990