Bug 860996 Changing Persona references to themes
Merge pull request #853 from retornam/bug-860996-remove-getpersonas

Bug 860996 Changing Persona references to themes
Fix bug 867810 - update /features page content

* Changed "Personas" to "Themes"
* Changed "App Tabs" to "Pinned Tabs"
* Updated SuMo link for pinned tabs