BLE Gatt Client Socket write and notify implementation

BLE Gatt Client Socket write and notify implementation

Client can write data using file descriptor on Characteristic
with property “write-without-response” . AcquireWrite
Method handler of bluez called to get write file descriptor.

Client can read notifications from File descriptors
on characteristics with property “Notify” .AcquireNotify
method handler of bluez called to get the notify file descriptor.

Change-Id: Idb06a14ae5368540f796d78e666d6896739c5579
Signed-off-by: Avichal Agarwal <avichal.a@samsung.com>