[Docker] Update run script with relative paths and docker-compose file

[nhandyal]

What changes were proposed in this pull request?

1. Update sparkler.sh to use relative paths and absolute paths to resolve sparkler jar directory
2. Update elasticsearch docker-compose.yml to specify bind volume using relative paths

'Closes #219 '.

How was this patch tested?

For changes to sparkler.sh

1. ran sparkler-core/sparkler-deployment/docker/elasticsearch/dockler.py --up. Logged into sparkler-elastic container. Ran sparkler to verify sparkler can be started when symlinked to /usr/bin. @buggtb to confirm if this fix resolves issue where sparkler.sh and jar are moved to different locations on disk

For changes to docker-compose.yml

1. ran docker inspect sparkler-elastic. Verified the bind volume path corresponded to the sparkler-core directory

   docker inspect sparkler-elastic
   "Mounts": [
   {
       "Type": "bind",
       "Source": "/Users/handyal/source/sparkler/sparkler-core",
       "Destination": "/data/sparkler-core",
       "Mode": "",
       "RW": true,
       "Propagation": "rprivate"
   }
   ],

[lewismc]

@buggtb can you please check. Gracias :)

[lewismc]

@buggtb please check. I'll merge by CoB today unless there are objections.

[buggtb]

Don't worry about this one, it didn't resolve the issue and we have a fix on the mvn2sbt branch that should sort it all out once we've got that branch ready for merging.