feat: Add Kafka functional tests

- Created test-kafka.yml workflow (384 lines, 5 tests)
- Tests Kafka 3.8.1 installation and core scripts
- Tests: server script, topics script, producer, consumer, Java dependency
- Downloads official Kafka binary distribution
- Installs Java 17 as dependency
- Added to test-all-packages.yml orchestrator
- Badge will display on kafka.md package page

Tests performed:
1. Check kafka-server-start.sh exists
2. Check kafka-topics.sh exists and runs
3. Check kafka-console-producer.sh exists
4. Check kafka-console-consumer.sh exists
5. Verify Java runtime available

Based on template-package-test.yml pattern

Author: pareenaverma

.github/workflows/test-all-packages.yml

@@ -24,13 +24,17 @@ jobs:
   test-envoy:
     uses: ./.github/workflows/test-envoy.yml
 
+  # Test kafka
+  test-kafka:
+    uses: ./.github/workflows/test-kafka.yml
+  
   # Add more packages here:
   # test-redis:
   #   uses: ./.github/workflows/test-redis.yml
 
   # Summary job that runs after all tests
   summary:
-    needs: [test-nginx, test-envoy]
+    needs: [test-nginx, test-envoy, test-kafka]
     runs-on: ubuntu-24.04-arm
     if: always()
     steps: