Add facter/openfact configuration support

[jay7x]

This PR is mostly based on idea of @vchepkov and implementation of @ikonia drafted in #950.

Closes #947

[ekohl]

Does this work?

Suggested change

	if $puppet::facter_config.length > 0 {
	unless empty($puppet::facter_config) {

[jay7x]

As $puppet::facter_config cannot be undef and is represented by Hash, so this should work (at least I'm always using it instead of emtpy() which is stdlib function).

➜ ~ puppet apply -e '$a={}; $b={foo=>"bar"}; notice $a.length; notice $b.length'
Notice: Scope(Class[main]): 0
Notice: Scope(Class[main]): 1

[jay7x]

This example should be better:

➜ ~ puppet apply -e '{}.with |Struct[{Optional[foo]=>String}] $x| { notice $x.length }'
Notice: Scope(Class[main]): 0
➜ ~ puppet apply -e '{foo=>"bar"}.with |Struct[{Optional[foo]=>String}] $x| { notice $x.length }'
Notice: Scope(Class[main]): 1

[jay7x]

I can change if empty() is preferred from a style perspective though :)

[jay7x]

JFYI, I tested this on my WIP puppetserver with bolt apply, and it works fine.

[ikonia]

thank you for taking this forward, I was struggling to get rid of the need for hocon_setting and hitting a wall