for comments - GEOMESA-233 adding scalding job to index attributes through geoserver UI

Still TODO - 
* create ticket for the TODO in the code
* error handling in UI for failed m/r jobs
* unit tests

(Tiny points) You can use underscores or omit named variables like this...
```
 .filter(_.isDirectory)
 .map(loadJarsFromFolder)
```
Also, what type is 'sys.env.get(home)'?  If it is already a Seq, you might not need the getOrElse.