*Motivation*

Currently fetching schema information is done synchronously.
It is called in netty callback threads and will potentially block
async operations.

*Modifications*

Make most of the operations asynchronously in SchemaInfoProvider.
(cherry picked from commit 91c4254c)

* o.a.p.c.api -> o.a.p.c.protocol

Classes in pulsar-common module were moved to avoid jpms split-package
conflict between the pulsar-client-api and pulsar-common modules.

* o.a.p.c.schema -> o.a.p.c.protocol.schema

Classes in pulsar-common module were moved to avoid jpms split-package
conflict between the pulsar-client-api and pulsar-common modules.

* Add multi version generic schema provider.

* fix log output and refactor get schema in lookup service.

* Add CLI commands for schema registry

* Rename commandline args

* Fix License Headers Issue

* - all schema structures used in rest apis should have default constructors
- change version to long in rest apis
- fix schema cli issues

* Add integration tests for Schema CLI

* Exclude schema example file from license check

* Exclude schema_example.conf from apache-rat:check

* Schema Registry proto changes

* Infrastructure to store schemas

* Renumber schema fields

* Update Pulsar API with schema changes

* Revert field number change

* Fix merge conflict

* Fix broken merge

* Address issues in review

* Add schema type back to proto definition

* Address comments regarding lombok usage

* Remove reserved future enum fields

* regenerate code from protobuf

* Remove unused code

* Add schema version to producer success message

* plumb schema through to producer

* Revert "Add schema version to producer success message"

This reverts commit e7e72f468cf46f1605524a7399520c22763583c9.

* Revert "Revert "Add schema version to producer success message""

This reverts commit 7b902f6bdb1cb054e26577747ff4dd8c326a6248.

* Persist schema on producer connect

* Add principal to schema on publish

* Reformat function for readability

* Remove unused protoc profile

* Rename put on schema registry to putIfAbsent

* wip: address review comments

* switch underscore to slash in schema name

* blah

* Fix protobuf version incompatibility

* Add appropriate license headers

* Utilities for arquillian integration tests

A set of utilities for working with clusters set up in arquillian.

- Utilities to work with docker
- Utilities to work with arquillian pulsar clusters
- Await strategies that arquillian uses to know if a node is up
- Stop actions to copy logs at the end of a test suite

* Move to log4j2

* Pull in extra dependencies for log4j yml configuration

* Updates headers with ASF source files header

* change license to additional files