I’m not saying it’s the best way… but a simple way of using a URL on the about page would be to paste something like this into your Admin
> Customize
>CSS/HTML
> </head>
<script type='text/x-handlebars' data-template-name='about'>
<div class='container body-page'>
<section class='about'>
<h2>{{i18n 'about.title' title=title}}</h2>
<p>{{description}}</p>
</section>
{{#if admins}}
<section class='about admins'>
<h3>{{i18n 'about.our_admins'}}</h3>
{{#each a in admins}}
{{user-small user=a}}
{{/each}}
<div class='clearfix'></div>
</section>
{{/if}}
{{#if moderators}}
<section class='about moderators'>
<h3>{{i18n 'about.our_moderators'}}</h3>
<div class='users'>
{{#each m in moderators}}
{{user-small user=m}}
{{/each}}
</div>
<div class='clearfix'></div>
</section>
{{/if}}
<section class='about stats'>
<h3>{{i18n 'about.stats'}}</h3>
<table class='table'>
<tr>
<th> </th>
<th>{{i18n 'about.stat.all_time'}}</th>
<th>{{i18n 'about.stat.last_7_days'}}</th>
</tr>
<tr>
<td class='title'>{{i18n 'about.topic_count'}}</td>
<td>{{number stats.topic_count}}</td>
<td>{{number stats.topics_7_days}}</td>
</tr>
<tr>
<td>{{i18n 'about.post_count'}}</td>
<td>{{number stats.post_count}}</td>
<td>{{number stats.posts_7_days}}</td>
</tr>
<tr>
<td>{{i18n 'about.user_count'}}</td>
<td>{{number stats.user_count}}</td>
<td>{{number stats.users_7_days}}</td>
</tr>
<tr>
<td>{{i18n 'about.like_count'}}</td>
<td>{{number stats.like_count}}</td>
<td>{{number stats.likes_7_days}}</td>
</tr>
</table>
</section>
<section class='about contact'>
<h3>{{i18n 'about.contact'}}</h3>
<p>You can always get in touch with us here: <a href="http://www.example.com/contact_form">Contact Form</a></p>
</section>
</div>
</script>
EDIT: this content was taken from the template and modified.
Hopefully the Discourse team will confirm this will allow you to leave your contact email in place in the settings.