Today when we send a signal we don't wait for the container to exit, as
we don't know what signals the program will actually do anything with.
However, sigkill does not fit this mold, and we should wait for the
container to exit (or be removed for --rm containers).
- Refactor network model types: replace `NetworkState` enum and
phase-based NetworkStatus with a flat `NetworkStatus` struct.
- Simplify API server ↔ plugin protocol: plugin `status()` returns
runtime status only, API server owns configuration.
- `NetworksService` `list()`/`create()` now return `NetworkResource`
directly.
- Remove lifecycle phase checks and state machine guards throughout CLI
and API server.
- `variant` is plugin-specific, it's not a required property. This PR
replaces `NetworkPluginInfo` with a `plugin` name property on
`NetworkConfiguration` and an `options` list similar to that for
volumes.
- Moved `variant` to the option list.
Danny Canter