[feat][CI] Replace the Golang based license_test.go with Apache Rat check in CI

[lhotari]

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

There's currently a Golang application to check licenses. This should be replaced with the usage of Apache Rat as we do in the
release process.

Describe the solution you'd like
Switch to use Apache Rat.

Describe alternatives you've considered
None.

Additional context

• GitHub Actions build job:

  pulsar-helm-chart/.github/workflows/pulsar-helm-chart-ci.yaml

  Lines 62 to 80 in 0a45f77

  	license-check:
  	needs: preconditions
  	name: License Check
  	runs-on: ubuntu-22.04
  	timeout-minutes: 10
  	if: ${{ needs.preconditions.outputs.docs_only != 'true' }}
  	steps:
  	- name: Set up Go 1.12
  	uses: actions/setup-go@v4
  	with:
  	go-version: 1.12
  	id: go
  	- name: Check out code into the Go module directory
  	uses: actions/checkout@v4
  	- name: Check license
  	run: |
  	go test license_test.go

• Apache Rat usage in vote email template: https://github.com/apache/pulsar-helm-chart/blob/master/RELEASE.md#prepare-vote-email-on-the-apache-pulsar-release-candidate