Remove all inline microdata from plugin/theme review templates

[jonoaldersonwp]

Review templates, like ​https://wordpress.org/support/plugin/tweet-old-post/reviews/ and ​https://wordpress.org/support/theme/twentyseventeen/reviews/, contain inline microdata (such as aggregateRating properties on .review-ratings).

However, almost all of this markup is incorrect and/or outdated.

It should be removed, as a precursor to a follow-up ticket which will define and implement the (correct) JSON-ID approach.

Specifically, the following should be removed from the whole template:

• Any <meta> tags used inline to house itemprop or similar properties (e.g., <meta itemprop="price" content="0.00" />).
• Any itemprop properties.
• Any itemtype properties.
• Any itemscope properties.

[dd32]

As with #5037 lets define the new JSON-ID format before we remove the existing tags.

[jonoaldersonwp]

The replacement JSON is much more complex on these templates, to the point that I'm tempted to ice-box it for now until we've done a bunch more housekeeping elsewhere.

Can we just strip the existing stuff for now, as it's throwing errors in GSC and occluding other issues.

[dufresnesteven]

Remove inline microdata

[coffee2code]

In 9600:

Support Forums, Ratings: Remove inline microdata from plugin/theme review templates.

Props dufresnesteven, jonoaldersonwp.
Fixes #5043.