Support environment variables for initContainer

[klit-la]

What would you like to be added?

With !1772 kompose supports defining initContainers via labels. Thanks for that! Now it would be great to define environment variables also via labels, such as kompose.init.containers.env

Why is this needed?

I have an application that needs to start prior to the actual application to initialize a postgres schema and the connection details need to be provided via environment variables.

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[klit-la]

/remove-lifecycle stale