Apply spark.app.name and spark.app.id as labels to the created pods

[ash211]

Automatically add spark.app.name and spark.app.id as labels to pods. This makes selecting pods by an ID easier. See #32 (comment)

Also note that this follows a similar pattern as other k8s controllers like Job: https://kubernetes.io/docs/user-guide/jobs/#running-an-example-job

[mccheah]

Added it for spark.app.name to #23 as an incidental fix to the integration tests.

Edit: Ah, this only adds the label for the driver - have yet to fix the executors.

[foxish]

This is done, closing.