deprecate "top-level" network information in NetworkSettings
deprecate "top-level" network information in NetworkSettings

When inspecting a container, `NetworkSettings` contains top-level
information about the default ("bridge") network;

`EndpointID`, `Gateway`, `GlobalIPv6Address`, `GlobalIPv6PrefixLen`,
`IPAddress`, `IPPrefixLen`, `IPv6Gateway`, and `MacAddress`.

These properties are deprecated in favor of per-network properties in
`NetworkSettings.Networks`. These properties were already "deprecated" in
docker 1.9, but kept around for backward compatibility.

Refer to [#17538](https://github.com/docker/docker/pull/17538) for further
information.

This officially deprecates these properties, and marks them
for removal in 1.16

Signed-off-by: Sebastiaan van Stijn <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@gone.nl>

e11137/cli,dnephin/cli,redpanda/cli,ashfall/cli,dnephin/cli,allencloud/cli,cpuguy83/cli,thaJeztah/cli,Zebrilee/cli,thaJeztah/cli,Zebrilee/cli,ashfall/cli,docker/cli,redpanda/cli,riyazdf/cli,cpuguy83/cli,e11137/cli,riyazdf/cli,allencloud/cli,docker/cli