Add user map

Replace the "contact" page with a "user" page that displays a map of SWIFT users.

I also anything related to the "talks" page, since it's well out of date, and isn't being added to the webpage anyway.

data/contact.md

-## Contact Us
-
-Hello there!
-
-You can easily reach the team via our <a href="https://app.gitter.im/#/room/#swiftsim_Lobby:gitter.im">Gitter</a>.
-
-### E-mail
-
-You can also join our <a href="https://mail.strw.leidenuniv.nl/mailman/listinfo/swift-users">mailing list</a>.
-This is a low-traffic, announcement-only list to keep updated on releases and other important changes.
-
-Alternatively, you can contact us using the form below. <br/>
-
-<form action="https://formspree.io/f/xzbqkdyk" method="POST">
-<label for="name"><h4>Name</h4></label>
-<input type="text" name="name">
-<label for="email"><h4>Email</h4></label>
-<input type="email" name="_replyto">
-<label for="content"><h4>Content</h4></label>
-<textarea name="content" placeholder="Your message here..."></textarea>
-
-<input type="hidden" name="_subject" id="email-subject" value="Contact Form Submission">
-<input type="submit" value="Send" class="btn btn-blue send">
-</form>
-
-### Postal
-
-If you would prefer to contact us through the post, you can do that at the following address:
-
-The SWIFT team (M. Schaller) <br/>
-Instituut-Lorentz for Theoretical Physics  <br/>
-P.O. Box 9506 <br/>
-NL-2300 RA Leiden <br/>
-The Netherlands <br/>