The checksyle plugin was added to the pulsar sql module to enforce the defined style. All violations were fixed:

- Ordering of imports.
- Formatting of the code.
- Absent Javadoc comments.
- Other small issues.
(cherry picked from commit f6fee1c6)

* adding module for Pulsar SQL

* renaming presto pulsar package

* fixing pom and configs

* fixing pom

* using project version variable in pom

* adding comments

* adding window function

* regenerating Function proto for python

* refactoring windowing code based on comments

* fixing tests

* add missing license header

* removing unnecessary imports

* removing another unnecessary import

* add note on multiple input topics

* fix CSS for highlight blocks

* more java API docs

* fix scrolling issue

* add CLI documentation for pulsar-admin functions

* fix YAML issues

* add PF to features list on front page

* add note about SPEs to feature description

* remove unnecessary include in local config

* add new badges to templates

* add section on core programming modeL

* add section on the SDK

* begin adding section on java sdk

* comparison table for native vs SDK

* add decrementCounter method

* add link

* add counters section

* update example functions

* revert Context object to master

* add user config section for java

* fix misspelling in error output

* add new PF config to YAML descriptor

* add processing guarantees doc to the sidebar

* update download URL and add trigger command to CLI docs

* add logTopic flag to CLI docs

* use native python function in quickstart

* add intro to java section

* update example functions and finish draft of API doc

* fix URL in sidebar config

* finish user config section in API doc

* add example ContextFunction

* finish draft of processing guarantees doc

* add section on triggering

* comment out subscription types section for now

* remove unnecessary console.log statement

* remove <hr> in docs template

* add missing DefaultSerDe class import

* fix error output to match test expectation

* Add missing license header to new example Pulsar Function

* Renamed RequestHandler to PulsarFunction

* Fixed header

* Create pulsar-functions module (#1)

* Create pulsar-functions module

* rename `sdk` package to `api`

* Added the first cut of the Java interface for Pulsar functions (#2)

* Cleaned up the logic of supported types

* Create pulsar-functions module (#1)

* Create pulsar-functions module

* rename `sdk` package to `api`

* Added the first cut of the Java interface for Pulsar functions (#2)

* Don't wait for the result. Instead chain it via CompletedFuture

* Integrate spawner in cli

* add scripts to run pulsar functions

* add example

* Make pulsar-functions run

* Create pulsar-functions module (#1)

* Create pulsar-functions module

* rename `sdk` package to `api`

* Added the first cut of the Java interface for Pulsar functions (#2)

* Added a simple example

* 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