Add radio buttons for choosing the API key type

Best-guess wording for what the labels and question should be.

Adds a macro for rendering radio buttons from a WTForms field.

app/templates/components/radios.html

@@ -0,0 +1,23 @@
+{% macro radios(
+  field,
+  hint=None
+) %}
+  <div class="form-group {% if field.errors %} error{% endif %}">
+    <fieldset>
+      <legend class="form-label">
+        {{ field.label }}
+        {% if field.errors %}
+          <span class="error-message">
+            {{ field.errors[0] }}
+          </span>
+        {% endif %}
+      </legend>
+      {% for option in field %}
+        <label class="block-label" for="{{ option.id }}">
+          {{ option }}
+          {{ option.label.text }}
+        </label>
+      {% endfor %}
+    </fieldset>
+  </div>
+{% endmacro %}

app/templates/views/api-keys/create.html

@@ -1,6 +1,7 @@
 {% extends "withnav_template.html" %}
 {% from "components/page-footer.html" import page_footer %}
 {% from "components/textbox.html" import textbox %}
+{% from "components/radios.html" import radios %}
 
 {% block page_title %}
   Add a new API key – GOV.UK Notify
@@ -13,7 +14,8 @@
   </h1>
 
   <form method="post">
-    {{ textbox(key_name, hint='eg CRM application') }}
+    {{ radios(form.key_type) }}
+    {{ textbox(form.key_name, label='Name for this key') }}
     {{ page_footer('Continue') }}
   </form>