Add suport for freebsd package resource

[fzipi]

Description

This PR adds support for testing using package resources in FreeBSD.

Related Issue

Created #4788.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New content (non-breaking change)
• Breaking change (a content change which would break existing functionality or processes)

Checklist:

• [ x ] I have read the CONTRIBUTING document.

[chef-expeditor]

Hello fzipi! Thanks for the pull request!

Here is what will happen next:

1. Your PR will be reviewed by the maintainers.
2. Possible Outcomes
   a. If everything looks good, one of them will approve it, and your PR will be merged.
   b. The maintainer may request follow-on work (e.g. code fix, linting, etc). We would encourage you to address this work in 2-3 business days to keep the conversation going and to get your contribution in sooner.
   c. Cases exist where a PR is neither aligned to Chef InSpec's product roadmap, or something the team can own or maintain long-term. In these cases, the maintainer will provide justification and close out the PR.

Thank you for contributing!

[zenspider]

The failures on BK have nothing to do with your PR and everything to do with rubygems breaking things in the latest version. Ignore that for now. I have a PR coming shortly that should fix things. Rebasing against master once that goes in should clear this up.

[zenspider]

Merged... Please rebase against master and force push.

[zenspider]

Minor nit (not need to fix unless you want to). Needs a rebase against master for proper CI. After that goes green, this should be good to go.