net: sockev: Initial Commit

Added module which subscribes to socket notifier events. Notifier events
are then converted to a multicast netlink message for user space
applications to consume.

CRs-Fixed:  626021
Change-Id: Id5c6808d972b69f5f065d7fba9094e75c6ad0b2c
Signed-off-by: Harout Hedeshian <harouth@codeaurora.org>