nebula-service -test -config should warn about unknown keys and stuff in config yaml

[fooryo]

Idea came from a typo on a yml file.
My yaml was like:

lighthose:
  [...]
  hosts:
    - stuff in here

but nebula-service -test -config host.yml just told me:
WARN[0000] No lighthouse.hosts configured, this host will only be able to initiate tunnels with static_host_map entries

I know that the message is self explanatory but could be and idea that it reports also something like
there is no lighthose on nebula config yaml schema or lighthose key is not an expected key?

A json/yaml schema could also help with the fact that a lighthouse config should not have any lighthouse.hosts in the yaml ( I didnt research why tho ) and helps with a manual writing of such config files.

Thanks

[johnmaguire]

Thanks for the idea. This has been discussed in various contexts before, so I went ahead and filed a FR issue for it based on your feedback. Cheers!