net: context: Add packet socket support

This commit adds basic packet socket support to net_context and
allows application to receive or send network packets in raw
format.

Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Ravi kumar Veeramally <ravikumar.veeramally@linux.intel.com>