Move the Akanda Networking panel in the new Manage Network section

In the Grizzly version of Horizon the navigation tree on the left
is been split in two section, this fix move the Akanda Networking
panel from the Manage Compute sections to the newly created
Manage Network section.

Change-Id: Iea6156bcc85496e3efac8c2bf4c50543dfb11a3d
Signed-off-by: Rosario Di Somma <rosario.disomma@dreamhost.com>