Mirror command: Read configurations from a config file

[bhumikagoyal]

Current: ./kat mirror --source-broker-ips broker1,broker2 --destination-broker-ips broker1,broker2 --topics topic1,topic2 o/p: Mirror all configurations for the specicifed topics.

Expected: Mention the configs to mirror in a config file and apply only those configs. This provides flexibility to users.