Evkafka

**Added**
- Add produced events to AsyncApi schema

**Fixed**
- Remove incorrect import from non required dependency 'kafka-python'

**Added**
- Declarative definition of produced events via `Sender.event`

**Added**
- Basic AsyncApi schema generation
- NOTICE.md

**Updated**
- Documentation for `ConsumerConfig`, `ProducerConfig`
- **breaking**: remove `max_poll_interval_ms`, `rebalance_timeout_ms` from consumer
config, replace with `max_endpoint_exec_time_ms`

**Added**
- `pre-commit` and `post-commit` consumer mode

**Updated**
- TestClient accepts non encoded event

**Removed**
- `enable_auto_commit` from consumer config

**Added**:
- Message decode logic is moved to a middleware

**Updated**
- Context obj new field 'decoded_value_cb'
- **breaking**: request.json is now awaitable