package will only include your code, none of your dependencies is added to your JAR you need to manually add them to the CLASSPATH
You may look into sbt-assembly & sbt-native-packager for alternative ways of producing an uber JAR or other kinds of self-contained executables.
But, no idea if that is a good idea with HDFS, AFAIK, your cluster should already provide those JARS; my only experience with Hadoop related projects is that the classpath is a nightmare and you will always do something wrong.