The Monasca Log API has been removed and in this change we switch
to using the unified API. If dedicated log APIs are required then
this can be supported through configuration. Out of the box the
Monasca API is used for both logs and metrics which is envisaged to
work for most use cases.

In order to use the unified API for logs, we need to disable the
legacy Kafka client. We also rename the Monasca API config file
to remove a warning about using the old style name.

Depends-On: https://review.opendev.org/#/c/728638
Change-Id: I9b6bf5b6690f4b4b3445e7d15a40e45dd42d2e84