fix: replace messaging.type with messaging.system

docs: add guide to migrate from v3 to v4

feat: upgrade to Confluent.Kafka.* 2.8.0

feat: upgrade to Confluent.Kafka.* 2.8.0

feat: upgrade to Confluent.Kafka.* 2.8.0

feat: upgrade to Confluent.Kafka.* 2.8.0

feat: upgrade to Confluent.Kafka.* 2.8.0

feat: add sample project to evaluate cooperative sticky strategy support

test: add unit tests and fix bug in ClusterConfiguration

- Added 3 new test files to improve coverage:
  - ConsumerConfigurationBuilderTests.cs
  - KafkaConfigTests.cs
  - PartitionAssignmentStrategyTests.cs
- Fixed a bug in ClusterConfiguration related to AutoCommitInterval initialization

chore: update AutoCommitInterval to 100ms in Cooperative-sticky sample

- Updated AutoCommitInterval in Cooperative-sticky sample Program.cs to 100ms.

fix: resolve Codacy issues

- Fixed various code quality issues flagged by Codacy.

feat: upgrade to Confluent.Kafka.* 2.8.0

fix: stop flow manager after calling revoke handlers