Update the elytron-tool.sh script to make use of jboss-modules.

This will mean that anyone currently running the tool with java -jar would need to update the command they use to do this. However, the documentation only mentions elytron-tool.sh so it's not clear how widely java -jar is actually used.

One option might be to update the jar to call the script. Another option might be to have the jar report an error that indicates that the script should be used instead.

The main steps will be to:

1. Add a new module for elytron-tool (take a look at existing modules here)
2. Update the elytron-tool scripts to make use of jboss-modules (as an example, take a look at the add-user.sh script here)
3. Figure out what to do if someone still tries to use java -jar
4. Determine what steps to take in the wildfly-elytron repo (ELY-2251)