Resetting some settings on starting a new demo session

Muting ringer and media volume and turning off the flashlight
before starting a new session. Also, resetting the configuration of any
new demo user to the configuration of user 0 on the device. Moved
RetailDemoModeService and RetailDemoModeServiceInternal to more
appropriate new packages

Bug: 29519612
Change-Id: Ib65f89ce61afab2d2f1b2dd0c761f5d35a466181