Direct users to renewal page on Store instead of /join

/join should only be used when someone can actually buy a new subscription.
/renew should be used when someone already has a subscription that needs
to be renewed.

Since url_for('cloud.xxxx') makes no sense in Pillar, I just hard-coded
/renew instead.

src/templates/nodes/custom/comment/list_embed.pug

@@ -49,6 +49,9 @@
 					| {% if current_user.has_cap('subscriber') %}
 					i.pi-lock
 					|  Only project members can comment.
+					| {% elif current_user.has_cap('can-renew-subscription') %}
+					i.pi-heart
+					a(href='/renew', target='_blank') Renew your subscription to join the conversation!
 					| {% else %}
 					| Join the conversation!&nbsp;<a href="https://store.blender.org/product/membership/">Subscribe to Blender Cloud</a> now.
 					| {% endif %}