Move atlassian-user-1 implementation from Crowd into Bamboo

Bamboo uses Crowd's crowd-integration-atlassian-user-1 (as part of crowd-integration-client) to connect to Crowd. Work to enable dynamic configuration has meant a number of changes here that needed full releases of Crowd to make it available to Bamboo. The module should be moved into Bamboo and used directly, depending on release versions of Crowd for the client libraries.