Normalize some extensions layout

Use the template extension-unittests

cldr
CirrusSearch
DonationInterface
EventLogging
Flow
GuidedTour
Mantle
TemplateData
Translate
TranslationNotifications
TwnMainPage
UniversalLanguageSelector
Workflow (got rid of alias)

Change-Id: I23f35b797f21bc62c6802fa85f26506f1118c17f