Work with community to use Puppet::Util::Execution.execute in hiera-eyaml[-gpg]

Hiera-eyaml is the current way that most folks secure their secrets between master and agent. Some integrations, most notably gpg, require shelling out to external CLIs to do their work. When code running in Puppet does that it should be using Puppet::Util::Execution.execute. This has been considered a nice-to-have for a long time, but with folks scaling Java based Puppet Servers to larger and larger sizes using the execution helper becomes more and more critical (since spawning processes from a large JVM is problematic on most linuxes).

The Server team should work with the community to utilize Puppet::Util::Execution.execute in hiera-eyaml in the long term and hiera-eyaml-gpg specifically in the short term.