[Appliance] Add Kafka service

[gtanzillo]

Spinoff from #374

This should be similar to how we supply PostgreSQL out of the box on our appliance. Basic Kafka with no HA or anything special. If user wants an HA and/or a customized external Kafka. we should allow for that configuration as well.

• Add kafka to the appliance as a RPM dependency Add dependency on the kafka package manageiq-rpm_build#91
• Bump appliance_console minimum: Bump manageiq-appliance_console minimum to include the Kafka work manageiq-appliance#310
• Appliance Console work to configure and enable the services
  • Issue: Automate Kafka configuration in the Appliance Console manageiq-appliance_console#125
  • PR: Initial commit of kafka server configuration manageiq-appliance_console#130

    Outstanding Issues:

    • Investigate if logs directory should be moved to /var/log [Specifying ref that contains dash doesn't work properly #130 (comment)].
      (Initial commit of kafka server configuration manageiq-appliance_console#130 (comment))

    • Investigate moving the persistent Kafka queue messages, to a dedicated another volume

    • Investigate if there is anything else that can be done to protect the passwords on the command line https://github.com/ManageIQ/manageiq-appliance_console/pull/130/files#r526476752

    • Once client configuration is complete on a server, switch Setting to kafka
      
      See: https://github.com/ManageIQ/manageiq/blob/2f8ae2345eb25b16ad87f7dc124b4fe68a610bdb/config/settings.yml#L936 to kafka.
      Pull Requests: #137 and #20837

    • Combine Kafka client configuration for external server and ManageIQ server

    • Update appliance_console CLI to enable/disable kafka

    • Update appliance_console kafka client configuration to disable the kafka server

    • Create a kick start to build images with the kafka server pre-configured

    • Get Kafka configuration working with Rdkafka

    • Investigate how to handle Kafka's apparent dependence on hostname

Outstanding PRs:

Should be ready to merge: ManageIQ/manageiq-rpm_build#122
WIP: ManageIQ/manageiq-appliance_console#137

[bdunne]

All boxes are checked. 🎉