Remove thirdparty dependency - jfreechart

With the removal of web-console there is no need for the jfreechart dependency:

<dependency>
<groupId>jfree</groupId>
<artifactId>jfreechart</artifactId>
<version>1.0.2</version>
</dependency>

<dependency>
<groupId>jfree</groupId>
<artifactId>jcommon</artifactId>
<version>1.0.2</version>
</dependency>