Check for URLs that are helpful to the Supermarket

[nathenharvey]

This PR introduces two new rules:

• FC064 - Ensure issues_url is set in metadata
• FC065 - Ensure source_url is set in metadata

In order to be able to share my cookbook on the Supermarket
As a developer
I want to be notified when my cookbook metadata does not specify the source_url or issues_url

I realize that not everyone who uses Foodcritic does so with the expectation that their cookbook will be shared on the Supermarket. As such, I'm proposing a new tag supermarket be added. Currently, I've tagged these two rules with both metadata and supermarket.

Implementing these two rules in Foodcritic will make the implementation of https://github.com/chef-cookbooks/cookbook-quality-metrics/ easier.

[coderanger]

These need to be disabled for versions of Chef which don't support the options.

[nathenharvey]

thanks, @coderanger. I've updated them to only apply to chef 12.0.0 or higher.

[robbkidd]

I propose the proposed supermarket tag be maybe collaboration. Thinking that things like issues_url facilitate collaboration no matter whether the cookbook is destined for public/private Supermarket or not.

[tas50]

👍 Much needed.

[nathenharvey]

Anyone have thoughts on @robbkidd's suggestion that the tag be collaboration instead of supermarket? While my interest lies primarily with the Supermarket for this PR, I do think collaboration better captures the nature of these rules.