Update to use the kie package structure

As an inexperienced user of Drools myself, I had no idea the previous package format was deprecated a long time ago to this kie package structure. This change-set updates to that package structure and will be compatible with drools >6. Interestingly, the dsl as an additional argument really isn't necessary as we just load in all the files necessary into the kieFileSystem, but I've left it separate for clarity.

I realize you may not be wanting to upgrade yet, but if you want to use Java8 features an upgrade is necessary.