(#8797) Merge puppetlabs-functions into puppetlabs-stdlib

(#8797) Merge puppetlabs-functions into puppetlabs-stdlib

It was decided that maintaining puppetlabs-functions and
puppetlabs-stdlib was duplication as both are trying to
achieve the same goal.

This patch provides a merge of the puppetlabs-functions
into the puppetlabs-stdlib repository, with history
preservation.

The following conflicts were found and resolved:

* LICENSE file from functions was used as it aligns with
  ASL usage instructions and contains relevant copyright
  information:
  http://www.apache.org/licenses/LICENSE-2.0.html
* Used spec_helper.rb from functions - this is what
  Puppet core uses and doesn't break tests.
* Merged .gitignore and spec.opts options.