Fixes #4791

**Motivation**

Currently the Pulsar Kafka wrapper is using Kafka 0.10.x version. However, there are users who use legacy-kafka version in their system and willing to move to pulsar. This PR provides pulsar-kafka adapter for kafka-api-version 0.9.X. So, this adapter can help users in their migration process from kafka-0.9 to pulsar.

* Removed shading relocations for Circe-checksum and lz4 libraries

* Also remove the jni shading in pulsar-broker-shaded

* Removed remaining relocations directives

* Moved Kafka wrapper tests to integration tests

* Do not shade io.netty.buffer.ByteBuf since it's passed between components

* Fixed presto dependencies license file

* adding a module that shades managed-ledger

* removing commented out lines

Signed-off-by: NSijie Guo <sijie@apache.org>

* Provide unshaded pulsar-kafka-client

* update doc

* comment on classes

* Added Kafka Source and Kafka Sink to Pulsar Connect

* Standardize on kafka versions for compat and connect

* Add hostname-verification at client tls connection

* add httpclient dep with exclude all + add pem in apache-rat

* add httpclient+commons-logging dep in client-shading and LICENSE

* shade artifacts

* fix: proxy send certs to client for host verification

* Upgrade to Netty-4.1

* Updated Recycler usages

* Converted usages of ByteBuf.order()

* Upgrade AsyncHttpClient

* Upgraded BK to 4.3.1.82-yahoo

* Fixed method name that changed in async-http-client-2.1

* Upgrade to Guava 20.0 to match same BK version

* Converted usages of templatized Recycler in protobuf generated code

* Fixed capacity in DoubleByteBuf

* Fixed usages of Objects.toStringHelper

* Use same netty version as BK

* Fixed kafka compat tests

* Include AsyncHttpClient default properties file in shaded jar

* Added ref count check in DoubleByteBufTest

* Updates headers with ASF source files header

* change license to additional files