Create a single jar that contains all necessary files for checkstyle

[ttddyy]

While I was trying to set up spring-javaformat in IntelliJ checkstyle plugin, I encountered this issue.
This is because files required to run checkstyle are separated over two jar files - spring-javaformat-config.jar and spring-javaformat-checkstyle.jar.

It would be nice to have a single jar file that contains all the required files for checkstyle. Then, it simplifies the usage of running checkstyle in CLI, setting up the IntelliJ checkstyle plugin, etc.