(#9546) Add spec tests for external fact pluginsync
(#9546) Added external fact plugin sync support to plugin face
(#9546) Added feature detection support for external facts

External fact support in puppet core is dependent on facter commit
https://github.com/puppetlabs/facter/commit/6f19eeeef1c5c8e9cc84c44599e03a5c06a30abc
so we need to detect if the installed version of facter is capable
before executing the external fact code