Fixed tutorial to become runnable again

[holgerbrandl]

This PR fixes multiple issues

• Usage of no longer available gcloud CLI commands
• Use PROJECT_ID variable in kubernetes configuration
• Revised Log Sink configurations to become compatible with current CLI
• Missing Bucket Permissions for log sinks
• Incompatible use of DataFlow APIs
• Misc changes in logging format and runtime parameters

It also extends the documentation to become streamlined by using variables for project, bucket and bq-dataset.

It's still not using the very latest DataFlow APIs so for instance we need to define GOOGLE_APPLICATION_CREDENTIALS because auth credentials can not be pulled with the used version of the java APIs.

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