Link Mastodon Account in Support section

[herbetom]

In the Guru3 Support Section there is currently only a Link to the Twitter Account:

guru3/core/templates/support.html

Line 52 in 789a9ce

<li><a href="https://twitter.com/eventphone">Eventphone@Twitter</a></li>

It might be good to also (or only, depending on the continued use of the Twitter Account) Link the Eventphone Mastodon Account: https://chaos.social/@eventphone