Acceptance Tests

@sfranson Here is a WAR artifact to execute acceptance tests against the service. To do so:
1. From the parent directory: `mvn clean install`
2. From the acceptance directory: `mvn cargo:run`
3. From another console: `curl -X POST http://localhost:8080/test?uri=http://localhost:8080/stake-directory-server`

There is a bunch of stuff still to do but this gets us started. 

BTW, this pull request is based on pull-request #3. Merging this will merge them both, but it would be easier to review if you did #3 first.