Show more information about startup failures

Recently we've had several reports of corrupt databases (StartResult#DB_ERROR). Because these errors prevent the app from starting, we can't use crash reports or user feedback to learn about the cause.

We should expose more information about startup failures in the UI. This will involve returning the information from LifecycleManager#startService() and then attaching it to the intent that launches StartupFailureActivity. StartupFailureActivity should allow the user to copy the information so they can send it to us.