Tweak multi-step header for app provisioning

- add "context" option to StickyCTA
 - tweak styles to better-include context
 - add header text to translations

templates/applications/new/step_3.html

@@ -6,7 +6,7 @@
 
 {% block portfolio_header %}
   {% include "portfolios/header.html" %}
-  {{ StickyCTA(text=application.name) }}
+  {{ StickyCTA(text=('portfolios.applications.new.step_3_header' | translate({"application_name": application.name}) ), context="Step 3 of 3") }}
 {% endblock %}
 
 {% block application_content %}