In functions log topic appender, don't set producer name

[merlimat]

Motivation

When enabling log topic in functions, we shouldn't set the producer name, otherwise multiple function instances will fail to produce on the log topic.

At the same time:

• Increase batch time to have more batching (since the latency hit will not be important here)
• Enabled LZ4 compression, since it's always good for logs.

[merlimat]

run integration tests