[FLINK-8833] [sql-client] Create a SQL Client JSON format fat-jar

[twalthr]

What is the purpose of the change

This adds a JSON format fat jar for the SQL Client. Actually the jar is identical to the non-shaded jar but I would still add this for consistency in order to not confuse users.

Brief change log

• Release fat jar added

Verifying this change

Manually verified.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): yes
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Yarn/Mesos, ZooKeeper: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? not documented yet

[fhueske]

Since we are not shading anything we could also use the Maven JAR plugin:

<plugin>
        <groupId>org.apache.maven.plugins</groupId>
	<artifactId>maven-jar-plugin</artifactId>
	<version>3.0.2</version>
	<executions>
		<execution>
			<phase>package</phase>
			<goals>
				<goal>jar</goal>
			</goals>
			<configuration>
				<classifier>sql-jar</classifier>
			</configuration>
		</execution>
	</executions>
</plugin>

[twalthr]

Thanks for the hint @fhueske. I will the the jar plugin and merge this...