Adding Helm chart, updating Kafka configuration

I'm using this project in a Kubernetes environment and required a few changes:

• Added basic Helm chart that deploys 3 replicas in a StatefulSet
• Exposed producer compression.type configuration parameter as environment variable WSPROXY_KAFKA_PRODUCER_COMPRESSION_TYPE
• Updated parallelism from 100 to 10000 per guidance here: https://github.com/akka/alpakka-kafka/blob/v4.0.2/core/src/main/resources/reference.conf#L18-L20
  • I was seeing significant amount of dropped messages when producing at a high data rate, this change appears to have fixed it

Thank you for creating this high-quality, useful project!