Implement CI testing builds with multiple Atlassian products

[lehmannk]

Currently only a single Atlassian product is started upon integration tests. Many integration tests, however, require to access multiple Atlassian products while running. These are e.g. for Confluence:

• user-directories (crowd)
• application-links (eg. jira)
• gadgets (eg. jira)

We need the ability to launch multiple Atlassian servers in order to be able to execute all necessary integration tests. Currently some tests are already prepared for these tests. They are annotated with

@Ignore("cannot be executed because there is no default user with restricted access rights")

and can be found in the it.de.aservo.atlassian.confapi.rest package.