Remove setup steps that are PE specific

Previously we put all of the setup steps for all of Puppetlabs projects
in its test harness. As projects change the maintenance cost should be
shifted to the developers/projects that are changing. They are the best
to understand their particular projects setup/dependencies. We have
moved all of the PE setup tests into a separate repository but the
harness will still try to load these outdated setup steps. This cleans
up the duplicate and/or conflicting setup steps that are better specified in
the PE projects test suite.
Specify if we are doing a PE run via env var

Previously we determined if we were running a PE suite based on what
setup option was chosen. As we move the setup of test suite out of the
harness the flags that would have told us whether or not we were running
a PE suite are no longer of use. Ideally we would allow the project
being tested to override the host defaults for values, but this that
would be a larger change than is currently scoped. In the mean time this
patch allows setting an environment variable to determine wether or not
this is a PE or FOSS suite run.
Remove un-used and un-useful setup steps

This patch removes the post install Ruby check, several other unused
setup steps and the CLI references to PE specific setup steps that
should no longer be in the harness.
Improve host defaults for better interop between FOSS and PE
Merge pull request #440 from justinstoller/host_defaults

Improve host defaults for PE vs FOSS porting