bluetooth: add bluez and dbus build targets

Revert "ISSUE 6849488 Bluedroid stack, remove system/bluetooth."
This reverts commit a3ae43942586e1f2b08fdc46963c73826ad6648c.
bluetooth: remove bluedroid stack

Bluedroid stack is to be removed and replaced later with BlueZ
Bluetooth stack.

Change-Id: I01b01cf6576372d20a373d966e1902925f216d40
Revert "Delete various Bluetooth files for stack integration."

Reverting this commit essentially pulls back missing BlueZ files from
pre-4.2 AOSP.
This reverts commit 313a2167098ce8498db3a50d70724f260e8169c0.

Change-Id: Ib85b7485f33099076ca0f87a0ffd012dc294750a
bluetooth: add BlueZ files from AOSP version 4.1.2

Pulls back BlueZ Bluetooth stack files from Android
version 4.1.2.

Change-Id: I9c26d369ccdb7c79a443427a3a735ce479992ddc
bluetooth: fix various issues building BlueZ

Change-Id: I3c321593810bf42096483d978633fa9c43bab3bf
bluetooth: change Setting from Secure to Global for BlueZ

Fix issues arising from changing setting location. In AOSP
starting from 4.2 some Bluetooth settting moved from Secure
to Global.
bluetooth: fix memory leak
bluetooth: debug: better debug state machine
bluetooth: improve logging, change magic numbers to strings

Change magic numbers to meaningful constants when logging.
bluetooth: remove unused method and imports
bluetooth: give more time to start EventLoop
bluetooth: hack: enable extensive debug - only for tests
bluetooth: sync with upstream and make PBAP complie

Change-Id: I4186b5fa0bf843eecf8c06eb35f86b251eac66ae