Add pages for OAD examples

[ralfhandl]

Part of OAI/OpenAPI-Specification#3854

Each example to be shown on the site needs a small markdown file which pulls in the JSON and YAML files via an include:

---
layout: default
title: api-with-examples
parent: Example API Descriptions
---

{% comment %}
{% capture description %}
Insert description here, then remove comment tag above and endcomment tag below
{% endcapture %}
{% endcomment %}

{% include example-api-description.md name=page.title description=description %}

The title in the front matter determines which sibling JSON and YAML files are embedded in code blocks, the name of the markdown file itself is irrelevant, although it is nice to use the same basename as for the JSON and YAML files.

See rendering on https://ralfhandl.github.io/learn.openapis.org/examples/v3.1/non-oauth-scopes.html

[ralfhandl]

Don't yamlize examples

[handrews]

I'm assuming all the noise in the json/yaml files is auto-reformatting and didn't review it in detail (looks fine based on a skim).

I did check the markdown, page titles, and other files, and they all look good.

[miqui]

checked the md, looks good to me.