After this change users with non-declarative configs need to set
`services.home-assistant.config` to an `null`, or their
`configuration.yaml` will be overwritten.
The reason for this is that with rfc42 style defaults the config
attribute set will never be empty by default.
If people take the time to setup network-online.target correctly we
should wait for it. If they don't it's basically the same as
network.target anyway, so no harm done.
Over time I've seen multiple integrations that have dealt badly with
missing network connectivity at startup, this should alleviate further
pains.
The given example is now closer to a sane default people will want to
start with. It also displays the existance of extraComponents, a feature
that will receive more usage with home-assistant warning about
components that have completely migrated away from YAML configuration.
