added cromwell command for cori

Jie Guo wanted to know how to run a WDL on cori using the cromwell command for testing. So I gave her the command and added the steps to "code snippets" page in jaws docs.

You need to copy the cromwell_cori.conf file from jaws-tutorial-examples.

java -Dconfig.file=cromwell_cori.conf \
-Dbackend.providers.Local.config.dockerRoot=$(pwd)/cromwell-executions \
-Dbackend.default=Local \
-jar /global/cfs/projectdirs/jaws/cromwell/cromwell.jar run align_final.wdl -i inputs.json