(#14900) Add data bindings hiera-puppet support.

Data binding now supports the hiera-puppet backend. When looking up data
in Hiera we now call the Hiera#lookup function with the Puppet scope
object instead of the host's facts (Hash).

We also remove the need to fetch node facts for every lookup; the scope
object already contains this info. The scope object provides access to
Facter Facts via the Scope#[] method.

This patch includes updated tests.