Support for specifying address type in connection string for 'ble' backend

[sjanc]

'ble' backend only supports peer_id which assumes public address type,

add support for specyfing peer_addr and peer_addr_type (like in bhd)

[m-gorecki]

The problem is that BLE module's API does not provide address type information. We probably should try to find and use other Bluetooth module with better API.