[kafka/exporter] Provide a way to use custom partitioner implementation

[khushijain21]

Component(s)

kafka/exporter

Is your feature request related to a problem? Please describe.

User may want to partition batches by various methods such as round-robin, hashing etc.
Some of the out of the box implementation in franz-go are listed here https://pkg.go.dev/github.com/twmb/franz-go/pkg/kgo#BasicConsistentPartitioner.

Kafka exporter should also allow using these + any custom partitioning strategies.

Describe the solution you'd like

Expose a new field called record_partitioner or just partitioner field that also supports a custom partition along with the available ones on franz-go

record_partitioner:
  sticky:
  roundRobin: 
  leastBackUp:
  custom:
    // name of the extension implementing the custom partitioner

Describe alternatives you've considered

No response

Additional context

No response

Tip

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[github-actions]

Pinging code owners for exporter/kafka: @pavolloffay @MovieStoreGuy @axw @paulojmdias. See Adding Labels via Comments if you do not have permissions to add labels yourself. For example, comment '/label priority:p2 -needs-triage' to set the priority and remove the needs-triage label.

[paulojmdias]

I think it is a valid addition, and I would be happy to review it. 👍

[VihasMakwana]

I'll take this up.