[test] Add kafka admin api unit test (#1793)

Please don't use the admin APIs, and it is hard to support in KoP.

| Method | Is Support |

|------------------------------|-------------------------------------------------|
| createAcls | Don't support, use pulsar admin to manage acl. |
| deleteAcls | Don't support, use pulsar admin to manage acl. |
| describeAcls | Don't support, use pulsar admin to manage acl. |
| listAcls | Don't support, use pulsar admin to manage acl. |
| electLeaders | Don't support, it depends on the pulsar. |
| describeUserScramCredentials | Don't support |
| alterUserScramCredentials | Don't support |
| alterPartitionReassignments | Don't support |
| listPartitionReassignments | Don't support |
| describeDelegationToken | Don't support |
| createDelegationToken | Don't support |
| alterReplicaLogDirs | Don't support |
| describeReplicaLogDirs | Don't support |
| describeLogDirs | Don't support |

Can be supported in feature.

| Method | How to support. |

|------------------------------|------------------------------------------------|
| alterClientQuotas | Can use pulsar admin handle it. |
| describeClientQuotas | Can get it from pulsar admin. |
| deleteConsumerGroupOffsets | Can handle by group coordinator. |
| alterConfigs | Maybe can store in the metadata store. |
| incrementalAlterConfigs | Maybe can store in the metadata store. |

* Add kafka admin api unit test.

Check the box below.

Need to update docs?

- [ ] `doc-required`

  (If you need help on updating docs, create a doc issue)

- [x] `no-need-doc`

  (Please explain why)

- [ ] `doc`

  (If this PR contains doc changes)

(cherry picked from commit f0eda8e)

Author: Demogorgon314