Add container option in waitjob read namespace pod log

[RupakVeerla]

Resolves issue #133

• If there are multiple containers in a pod, wait job fails to get logs, so this change will choose a specific container to get logs from.
• It gets the container name from environment variable.
• If no container is specified, it will choose the default container to get the log.

[ltamaster]

Hi @RupakVeerla ,

Can we add the container field as an optional value, to no break existing configuration
thanks
Luis