Adding a generic BLE service for Trusted Device.

This provides the methods to start and function as a BLE GATT Server.
The Enrollment and Unlock services can use this for communicating with
the remote device via BLE.

This is part of the Car Service implementation for Trusted Device. To be
used by CarTrustAgentEnrollmentService in a subsequent Change.

Bug:120911995
Test: Build and flash.
Change-Id: I72be934290a2d8b12b0da6e55f4c7f897f199caa
1 file changed