LE CoC: Add FRWK APIs for L2CAP_LE type socket

LE CoC: Add FRWK APIs for L2CAP_LE type socket

This patch adds the following:
- Export APIs to create and remove L2CAP_LE socket
- Export APIs to listen, connect and disconnect to
L2CAP_LE socket
- Implement event handler for connection, disconnection
and authorization.

To avoid build conflict please merge this patch after merging bluez
patch: (Change-Id: I7f4f6ba5fe49b6d3fa05bfbc3a1b2bfdd269c6bb)

Change-Id: I7808664b833da9f0625b75d7fe4640fdd3cd52b3
Signed-off-by: Ayush Garg <ayush.garg@samsung.com>
Signed-off-by: Anuj Jain <anuj01.jain@samsung.com>