Move InMemoryDatabase setup into a module

Storing the injector in the InMemoryDatabase instance was a hack.
Instead, move towards a more comprehensive Guice stack for tests by
moving this setup into a module.

Keep the same manual create()/drop() behavior of InMemoryDatabase,
though eventually we may want to do something with LifecycleManagers
and move towards a similar idiom to that used in the acceptance tests.

Change-Id: I917f6dab4751541fa63bfe3318818fbe4bda20f2
5 files changed