Modify build.gradle s.t. enablePaAndRca uses a docker image with all ODFE plugins enabled

[sidheart]

Subtask for #22

Scope ESRestTestCase is a class provided by Elastic core which allows a user to executes REST based tests against an ElasticSearch cluster.

We have a gradle task called enablePaAndRca which spins up a 2-node cluster via docker-compose which has Rca enabled.

Either modify the enablePaAndRca task or write a new Gradle task which starts an ElasticSearch cluster which has all the opendistro-for-elasticsearch plugins enabled. This will allow us to verify the behavior of this plugin in an appropriate environment where its interactions with other plugins can be examined.

Acceptance Criteria The gradle task as described above exists. Any ESRestTestCases should execute against this image.