Consumers: Unsubscribe topics from consumer group

[p-eye]

• Breaking change? (if so, please describe the impact and migration path for existing application instances)

What changes did you make? (Give an overview)
As mentioned in issue #462, on the consumer group page, add a button to delete topic offsets. It should function similarly to the following command:

kafka-consumer-groups --bootstrap-server <server>
   --delete-offsets -group <group_name> \
   --topic <topic_1>

Is there anything you'd like reviewers to focus on?

How Has This Been Tested? (put an "x" (case-sensitive!) next to an item)

• No need to
• Manually (please, describe, if necessary)
• Unit checks
• Integration checks
• Covered by existing automation

Checklist (put an "x" (case-sensitive!) next to all the items, otherwise the build will fail)

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (e.g. ENVIRONMENT VARIABLES)
• My changes generate no new warnings (e.g. Sonar is happy)
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged

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[github-actions]

Hi p-eye! 👋

Welcome, and thank you for opening your first PR in the repo!

Please wait for triaging by our maintainers.

Please take a look at our contributing guide.

[p-eye]

@Haarolean Do you think the review might take a bit longer?
I would appreciate it if your team could review it.
thanks 😃

[Haarolean]

@Haarolean Do you think the review might take a bit longer? I would appreciate it if your team could review it. thanks 😃

it definitely will as I'm trying to wrap the things up for 1.1 release, while the other folks seem to be busy for a review :-)

[Haarolean]

One minor thing regarding delete -> reset naming, the rest (backend) looks good 👍🏼

[p-eye]

In addition, I removed unused imports.

[Haarolean]

@p-eye thank you for one more contribution!