Use description list (`dl`) element on show views

[Flo0807]

To improve a11y we should use a description list element on show views.

Each section (including the default one) should have its own description list with dt and dd elements.

So for the User show view the resulting markup should look something like this:

<!-- Default section without heading -->
<dl>
  <dt>Age</dt>
  <dd>30</dd>
    
  <dt>Role</dt>
  <dd>User</dd>
</dl>

<h2>Names</h2>
<dl>
  <dt>Username</dt>
  <dd>john_doe</dd>
    
  <dt>Full Name</dt>
  <dd>John Doe</dd>
</dl>