(FACT-3474) Update facter schema, CONTRIBUTING.md, and add acceptance test to verify facts conform to schema

[AriaXLi]

This PR:

• Updates facter.yaml to include any facts added since the schema was last
  updated
• Updates CONTRIBUTING.md so contributors know to add new facts to facter.yaml
  schema
• Adds an acceptance test that tests the facter output conforms to the schema
  on each platform

[AriaXLi]

ubuntu-20.04 failed because the disks.<devicename>.wwn fact doesn't currently exist in the schema...

[AriaXLi]

On Windows, the networking.interfaces.dhcp fact is returning "" instead of a valid IPv4 value. This causes the schema.rb acceptance test to fail since the dhcp fact is not conforming to the schema. Due to this, the test will temporarily not be run on Windows until FACT-3479 is resolved

[bastelfreak]

@AriaXLi thanks for the great PR! Do you know if there's an easy way for us to validate a factset, in json, against this schema? I'm asking because in FacterDB we collect a lot of factsets from running machines, but some are also generated with sed statements or manipulated.

[AriaXLi]

@AriaXLi thanks for the great PR! Do you know if there's an easy way for us to validate a factset, in json, against this schema? I'm asking because in FacterDB we collect a lot of factsets from running machines, but some are also generated with sed statements or manipulated.

Hi @bastelfreak thanks, glad I can help! Hmm I chose yaml since lib/schema/facter.yaml is yaml but I imagine you could probably use a factset in json by loading lib/schema/facter.yaml as a json file instead of yaml 🤔 not 100% sure though as I haven't tried it myself