(#8010) Add validate_hash function
(#8010) Add validate_hash function

This function validates all passed variables are hashes.  This is
similar to the validate_bool function and is copied from it.

yadavnikhil/puppetlabs-stdlib,HelenCampbell/puppetlabs-stdlib,jbondpdx/puppetlabs-stdlib,puppetlabs/puppetlabs-stdlib,fuel-infra/puppetlabs-stdlib,DavidS/puppetlabs-stdlib