Puppetize systemd override for Kafka LimitNOFILE

/etc/default/kafka's KAFKA_NOFILES_ULIMIT is not useable
by the systemd service file installed by the latest WMF
Kafka package, so we need to puppetized a custom systemd
override file to set this.

Bug: T106581
Change-Id: I10f41d0d3a19b15374ded800f0d6cd12573c9fa9