cli: adding support for partition and lag listing

[BlackPanther112358]

Which issue does this PR address?

Closes #4462
Relates to #

Rationale

This change adds details for partition offsets and lag on each partition of consumer group while running the command consumer-group get from the cli.

What changed?

Currently users need to make n+1 calls for checking partition offsets and lag for a consumer group - first run a consumer-group get and then for each partition run consumer-offset get which they want to see.

This PR centralizes calls into consumer-group get for fetching the partitions of the consumer group, and subsequently the members and offsets to calculate and render lag.

Local Execution

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AI Usage

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