Chore: add require-meta-docs-url internal rule

[mysticatea]

This PR adds require-meta-docs-url internal rule to verify meta.docs.url property on all rule files (related to #340). Details:

1. I found eslint-plugin-eslint-plugin rules use module.exports.create to distinguish whether a file is an ESLint rule or not. If the create property is not a method (e.g. a variable reference), eslint-plugin-eslint-plugin rules ignore the file. As the result, most rules in this plugin are ignored.
   6589d4a fixes the problem. It moves every craete function into the RHS of module.exports.
2. 61e3a4f adds require-meta-docs-url internal rule.
3. 404d433 applies the internal rule to our rules. And I improved those URL to version specific documents.
4. e7c3ec4 modifies npm version <type> script to update those URL by new version.

I have a plan to send require-meta-docs-url rule to eslint-plugin-eslint-plugin. After I have done it, I will send another PR to upgrade eslint-plugin-eslint-plugin plugin.

[michalsnik]

Hey, thank you for working on this :) Though I'd prefer to wait for the release of eslint-plugin-eslint-plugin I see it would be hard to work on other things without introducing more and more conflicts here.

[michalsnik]

Please resolve conflict and feel free to merge it @mysticatea :)

[mysticatea]

Thank you!

eslint-plugin/require-meta-docs-url was merged but not released yet. (eslint-community/eslint-plugin-eslint-plugin#56)