Adding ops JSON output to allow build web frontend

[dzonerzy]

Would be nice if ops could output information like instances and so on in a JSON format this way would be possible to create a web frontend by wrapping the ops command.

[eyberg]

this exists for many operations already like https://github.com/nanovms/ops/blob/master/gcp/gcp_instance.go#L210

[dzonerzy]

I don't know if already exist for onprem images , but that would be awesome

[eyberg]

proposal here would probably just be to tack on a '--json' flag to any of the commands vs default of table output

[eyberg]

need to remove the RunConfig.JSON bool and put it somewhere else (possibly in a new struct that interacts with the various flags)