Remove client-side validations

[bennypowers]

Elements like CTA, Footer, Navigation and others contain client side validations which log warnings via Logger whenever they find invalid HTML children.

For example, this (incorrect) HTML

<rh-cta>
  <p><a></a></p>
</rh-cta>

Will produce this message:

The first child in the light DOM must be a supported call-to-action tag (<a>, <button>)

The Problem

This means we're shipping validation code to pages which don't need it
and we're also logging developer-facing messages on customer-facing sites

Proposed Solution

I propose we remove all of these validations, and instead use a tool like @paceaux's Selector Hound or other extensible HTML validators to run validations out-of-band

[paceaux]

I've got an issue open on Selector Hound to see how we can work on this. Working from a manifest or a custom element registry may be a novel way to do this.

[bennypowers]

paceaux/selector-finder#39