adapter: Add ConnectDevice method

This allows to connect device without doing general discovery. This is
needed for some of qualification tests where there is no general
discovery upfront and we need to do connection to device with provided
address.

Another usecase is for scenario where scanning happen on one controller
but connection handling on another.

New device object is announced only if physical connection was
successful. On success this method returns path to created device
object. After ConnectProfile return bluetoothd continue with
services discovery and profile connection.

This patch implements bare minimum properties needed for connection -
address and address type. If needed eg. for non-NFC based OOB it could
be extended with more options.
3 files changed