✨ Combine dictionaries with host and group vars against default values.

[indigo423]

When using a dictionary with host_vars and group_vars they are not combined by default. If you set a few parameters in the group, the dictionary, the whole defaults dictionary is overwritten. We need to find a way how we can combine them.

Here is an example of the Kafka defaults. One way would be renaming the dictionaries from kafka_server_properties to kafka_server_properties_group and adding a new one kafka_server_properties_host with the defaults, and using the combine() method.