chore: Add documentation validation tool

[bradzacher]

Should wait on the rule barrel introduced in #313

Adds a script to validate:

The plugin docs:

• ensures every rule has a doc in the docs folder.

The root readme:

• ensures the rule table has the correct sorting
• ensures every non-deprecated rule has a row in the table
• ensures every row matches the rule's meta definition

[JamesHenry]

I don't see you calling this out in your description - why did your remove all the connections to TSLint rules?

[bradzacher]

I didn't see the point in specifically tracking that within the rule metadata when we have the ROADMAP.md which comprehensively lists it all.

Also half of them weren't working correctly because they used the wrong property name (and TS ignored that)

[JamesHenry]

Ok cool, because you hadn't called it out I was mainly checking you hadn't done it by accident