The default guava for Acceptance tests is version 15.

Had to set this to version 15 because JClouds will not be able to use any guava above 15 until they release 1.8.
XD-1545 Acc testing for multiple containers

1. Test no longer relies on artifact to know what containers are available.  This is queried from admin.
2. Test finds the container where source, processor, job & sink modules are deployed.
3. Mapped ec2 internal dns to external dns.
4. Tests handle x containers for source & job file based tests.
5. Sample properties container settings have been removed.
6. jclouds-ec2 dependency added to build.gradle.  It is compile time since it is utility based.
XD-1849: Move executions by name
XD-1849 Move launch endpoint
XD-1849 Changes on merge

- Make job launch as `POST` request
  - Update BatchJobExecutionsController
  - Fix test
  - Update REST client - `JobTemplate` method for job launch
  - Update job service in the admin UI
- Move the job launch test to `BatchJobExecutionsControllerIntegrationTests`