Improvement/Have `cscli hubtest` warn you when your parser has no `evt.Meta.source_ip`

[buixor]

For new users, it can be quite tricky to understand that evt.Meta.source_ip is expected for most event types, and things can get wrong easily when creating one.

I guess having cscli hubtest warn you when :

• your parser doesn't generate a Meta.source_ip
• your scenario's filter or group_by matches on a missing key
• When evt.StrTime is not filled It would be really useful