add user registration routes

* Added /register get and post routes.
+ Added default attributes to AnonymousUser, including a new
  AnonymousList which behaves like an sqlalchemy relationship
  list.
+ aurweb.util: Added validation functions for various user fields
  used throughout registration.
+ test_accounts_routes: Added get|post register route tests.

Signed-off-by: Kevin Morris <kevr@0cost.org>

templates/register.html

@@ -0,0 +1,30 @@
+{% extends "partials/layout.html" %}
+
+{% block pageContent %}
+    <div class="box">
+        <h2>{% trans %}Register{% endtrans %}</h2>
+
+        {% if complete %}
+            {{
+                "The account, %s%s%s, has been successfully created."
+                | tr
+                | format("<strong>", "'" + user.Username + "'", "</strong>")
+                | safe
+            }}
+            <p>
+                {% trans %}A password reset key has been sent to your e-mail address.{% endtrans %}
+            </p>
+        {% else %}
+            {% if errors %}
+                {% include "partials/error.html" %}
+            {% else %}
+                <p>
+                    {% trans %}Use this form to create an account.{% endtrans %}
+                </p>
+            {% endif %}
+
+            {% set form_type = "NewAccount" %}
+            {% include "partials/account_form.html" %}
+        {% endif %}
+    </div>
+{% endblock %}