Added validation to ensure user can't invite themselves.

Refactored Invited user form into permissions and invite forms
for use in invite and edit permissions.

Added template for edit permissions.

app/templates/views/edit-user-permissions.html

@@ -0,0 +1,43 @@
+{% extends "withnav_template.html" %}
+{% from "components/yes-no.html" import yes_no %}
+{% from "components/textbox.html" import textbox %}
+{% from "components/page-footer.html" import page_footer %}
+
+{% block page_title %}
+Manage users – GOV.UK Notify
+{% endblock %}
+
+{% block maincolumn_content %}
+
+  <h1 class="heading-large">
+    {{ user.name or user.email_localpart or "Add a new team member" }}
+  </h1>
+
+  <div class="grid-row">
+    <form method="post" class="column-three-quarters">
+
+      <fieldset class='yes-no-wrapper'>
+        <legend class='heading-small'>
+          Permissions
+        </legend>
+        <span class="form-hint">All team members can see message history</span>
+        {{ yes_no(form.send_messages.name, form.send_messages.label, form.send_messages.data) }}
+        {{ yes_no(form.manage_service.name, form.manage_service.label, form.manage_service.data) }}
+        {{ yes_no(form.manage_api_keys.name, form.manage_api_keys.label, form.manage_api_keys.data) }}
+      </fieldset>
+
+      {% if user %}
+        {{ page_footer(
+          'Save',
+          delete_link=url_for('.delete_user', service_id=service_id, user_id=user_id),
+          delete_link_text='Delete this account',
+          back_link=url_for('.manage_users', service_id=service_id),
+          back_link_text='Cancel'
+        ) }}
+      {% else %}
+        {{ page_footer('Send invitation email') }}
+      {% endif %}
+
+    </form>
+  </div>
+{% endblock %}