Re-add support for signups with unlock keys.

web/registration/start-with-key.html

+<p>Welcome, fellow traveler, on a new journey on the internet.</p>
+<p>This website will enable you to create a VPN account to use the service.
+    <br>
+    To control the amount of signups, we currently require you to have an unlock key
+    to be able to sign up. If you have not received such a key, and you're willing to do the following</p>
+<ul class="list-group">
+    <li class="list-group-item">Use our service</li>
+    <li class="list-group-item">Provide feedback</li>
+    <li class="list-group-item">Accept that Neutrinet currently makes no guarantees about the functionality nor security
+        of its
+        service. We are providing a lot of effort to make the VPN stable and as secure as possible, but
+        please refrain from using our network for critical applications (webshop, comms provider).
+    </li>
+    <li class="list-group-item">Have a drink with us! (we're people, too)</li>
+</ul>
+
+<p><a href="http://neutrinet.be/index.php?title=Contact" title="Contact">Contact</a>
+    us (IRC or mail), and we will likely provide you with one if we still have capacity left.</p>
+
+<h2>Sign up</h2>
+<p>You have an unlock key. We are building a great VPN service. Let's do this.</p>
+<form action="#" role="form">
+    <div class="form-group">
+        <label class="label control-label" for="signup-email">Email address</label><input class="form-control"
+                                                                                          type="text"
+                                                                                          id="signup-email"/><br>
+    </div>
+    <div class="form-group">
+        <label class="label control-label" for="signup-key">Unlock key</label><input class="form-control"
+                                                                                     id="signup-key" type="text"/><br>
+    </div>
+    <input class="btn btn-primary form-control" type="button" value="Sign up!"/>
+</form>
+<h2>Unlock key policy</h2>
+<p>Neutrinet ASBL keeps the right to hand out and retract unlock keys at its sole discretion.
+    We handle ad-hoc requests by following guidelines:</p>
+
+<ul class="list-group">
+    <li class="list-group-item">First come, first serve</li>
+    <li class="list-group-item">One key per person</li>
+    <li class="list-group-item">Unlock keys are valid for 7 days, starting at the date of issuance</li>
+    <li class="list-group-item">When re-applying, your request is placed at the end of the queue</li>
+    <li class="list-group-item">When using the unlock key with an e-mail address other than the one it has been sent
+        to, please allow us some time to verify both email addresses are used by the same person.
+    </li>
+</ul>
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