Generate JSON Schema from Configuration POJO

[sylvaingaudan]

It is possible, with jackson, to generate the JSON schema of a POJO. This should be done for the
ArlasServerConfiguration class.

The mkDocs.sh should place the generated file within the generated documentation folder.

<plugin>
 <groupId>com.fasterxml.jackson</groupId>
 <artifactId>jackson-json-schema-plugin</artifactId>
...
</plugin>

See http://fasterxml.github.io/jackson-schema-maven-plugin/jackson-json-schema-plugin/usage.html for usage details.