* Create AnalyticsServiceProtocol and conform AnalyticsService
* Replace AnalyticsService properties and arguments with AnalyticsServiceProtocol
* Inline AnalyticsServiceMock replacing old mock
* handle more complex AnalyticsServiceMock callsites
* move documentation from AnalyticsService to AnalyticsServiceProtocol
Removes the ServiceLocator singleton and instead directly injects the dependencies it was holding for more control over instantiation of the various component subtrees and better visibility over how they're being used.
Squashed commits:
[d64bb3bb] Stop using the ServiceLocator directly in the ScreenTrackerViewModifier
[37c46ab9] Rename Analytics to AnalyticsService
[8852a371] #920 - Cleanup ServiceLocator usages