Refactor call blocking into InCallPresenter.

This retains CallList being context-independent, and consolidates
most of the logic. This makes InCallPresenter responsible for
calling into the CallList to add/remove/cleanup calls.

This will make it easier to hook in emergency call logic which needs
a Context to store the time an outgoing emergency call is made.

Also, remove the timeout runnable if the
BlockedNumberContentObserver unregisters after successfully
updating the call log.

Bug: 24418319
Change-Id: I6a203f5a260428f51e7965c73e3eee89edb949bd