bluetooth: Remove usage of bluetooth library 

In Bluez 5, the bluetooth library is deprecated, and not compiled by
default. Pulseaudio only depends on one function in the bluetooth
library, so let's copy it.
bluetooth: Declare endpoints for mSBC
bluetooth: Initialize transport codec

The codec depends on the endpoint requested by the transport.
bluetooth: Switch codec for hsp/hfgw
bluetooth: mSBC encoding and decoding

Now that the endpoints are declared, encoding and decoding can be implemented.