[Media TTT] Add the aidl interface for the sender and a service that

implements it.

More callbacks will be added in future CLs.

Bug: 203800643
Bug: 203800347
Test: manual (verify `adb shell cmd statusbar media-ttt-chip-add-sender
Tablet MoveCloserToTransfer` still triggers chip)
Test: media.taptotransfer tests

Change-Id: Ic44b770e8c98f7c9a06a0846fd166e4c8d51ea7d