Make timestamps in operator logs human-readable

[johananl]

At the moment the operator produces log messages in the following format:

{"level":"info","ts":1566906621.2220764,"logger":"controller_cassandradatacenter","msg":"CassandraDataCenter reconciliation complete.","Request.Namespace":"default","Request.Name":"cassandra-sample-dc"}

It might be nicer to have human-readable timestamps.

[smiklosovic]

I was briefly looking into this and I am not sure we can tweak that easily.

We would have to do more or less this:

uber-go/zap#485 (comment)

bypassing how k8s is doing that in sigs.k8s.io/controller-runtime/pkg/runtime/log package in func ZapLoggerTo(destWriter io.Writer, development bool) logr.Logger function.