Run acceptance tests requiring domain admin privilege #520

Currently there are tests requiring domain admin privilege in a special group isolated_domain which is never run and more over can't be run even manually (when excludedGroups is set in pom.xml it can't be overridden from command line).

• run all tests by default
• beware: domain argument for tests will be mandatory (there is currently no way how user can find his domain id)
• rename group isolated_domain to a more suitable name: domainAdmin?
• user without domain admin privilege should have the possibility to skip such tests - update documentation