[FEAT] Add support for Kafka Authentication

[DanHatesNumbers]

Is your feature request related to a problem? Please describe.
As a Kiln Administrator
I want Kiln components to add support for Kafka authentication
So that I can control access to my Kafka cluster

Describe the solution you'd like
Kafka supports a number of authentication mechanisms: GSSAPI (Kerberos), Plain, OAuthBearer, SASL SCRAM, Delegation tokens and mutually authenticated TLS. Kiln components should add support for at least one of these mechanisms to allow Kafka clusters to disallow unauthenticated connections.

Additional context
Simplest approach that maintains reasonable security is probably SASL SCRAM. We're already requiring that Kiln connects over TLS, this provides a salted challenge-response mechanism (https://tools.ietf.org/html/rfc5802 for details) and doesn't have the added complexity of managing client certificates.