[metadata]: add pinterest meta tag (#76988)
### What
Adds support for Pinterest's Rich Pin Data meta tag, while
future-proofing for additional Pinterest tags.
This currently works like so
```js
pinterest: {
richPin: true
}
```
And would resolve to:
```html
<meta property="pinterest-rich-pin" content="true" />
```
x-ref: https://help.pinterest.com/en/business/article/rich-pins
Closes #70873
---------
Co-authored-by: Dominik Koch <dominik@koch-bautechnik.de>
