* Continuation of https://github.com/trlinkin/puppet-nsswitch/pull/34 by
  @rcalixte
* Added support for EL8
* Added a `file_path` parameter to allow users to move the nsswitch.conf
  target
* Updated/fixed documentation for `puppet strings`
* Generated a REFERENCE.md and linked it to the README.md
* Updated the minimum required version of `puppetlabs-stdlib` for
  support for the `Stdlib::Unixpath` data type
* Updated the spec tests