Add partition based even scaling kafka scaler

[patelvp]

Issue: #2581
Enhance the Kafka Scaler or create a new KEDA Scaler to support scaling Kafka by partitions per pod as opposed to simple increase in pod count.

Checklist

• When introducing a new scaler, I agree with the scaling governance policy
• I have verified that my change is according to the deprecations & breaking changes policy
• Tests have been added
• Changelog has been updated and is aligned with our changelog requirements
• A PR is opened to update our Helm chart (repo) (if applicable, ie. when deployment manifests are modified)
• A PR is opened to update the documentation on (repo) (if applicable)
• Commits are signed with Developer Certificate of Origin (DCO - learn more)

Fixes #2581

Relates to #

QA:
Tested this locally by pushing an image on a local kind cluster. Kafka consumer and producers are outside the cluster to get granual and quick control over production and consumption rate.
Plotted the pod count and kafka partition lag onto grafana.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions.

[JorTurFer]

Is this still WIP? Can we review it or it's just abandoned?

[stale]

This issue has been automatically closed due to inactivity.

[patelvp]

Is this still WIP? Can we review it or it's just abandoned?

Sorry been on a vacation.

@JorTurFer I am waiting on some discussions here #2581 (comment)