Put the debug screen back into settings

There is still work to be done here:
* The debug setting is not persisted in Exchange, so if
the exchange service is killed, when it restarts the logging
will not be active.
* Nothing in Exchange actually does any additional logging
if this logging is turned on.

Change-Id: I5ec731791bf5297ee8d5ec4845f2e714b4bfa60f
2 files changed