Events (listing) page

[schalkneethling]

A couple of mostly structural issues to address on this page:

1. [x] The featured section's heading hierarchy is incorrect. The structure should be something like:

<div class="mzp-l-content">
  <h2>Featured</h2>

  <ul>
    <li class="mzp-c-card mzp-c-card-extra-small mzp-has-aspect-16-9">
      <a href="/events/oxidize-global-2020/" class="mzp-c-card-block-link" data-type="event">
        ...
        <h3 class="mzp-c-card-title">Oxidize Global 2020</h3>
      </a>
    <li>
  </ul>
</div>

2. [x] The community events section's heading hierarchy is incorrect. The structure should be something like:

<div class="mzp-l-content events-middle-content">      
  <div class="rich-text">
    <h2>Community Events</h2>

Each entry in the results list should then use an h3 element as its heading.

3. [x] The results list should be ideally marked up as a list

[valgrimm]

Val has fixed "The community events section's heading hierarchy is incorrect"

[stevejalim]

The featured section's heading hierarchy is incorrect. The structure should be something like:

This was addressed in as part of #1736

[stevejalim]

Only thing remaining is:

The results list should be ideally marked up as a list

Which is the filter-list.html used on Posts, Events and People

[stevejalim]

https://github.com/mdn/developer-portal/pull/1761 addresses The results list should be ideally marked up as a list