Update Bamboo->JIRA integration documentation (project applink in 3.2.x)

I think we need to make documentation better in the area of Bamboo->Jira integration. We added in Bamboo 3.2 a feature "project link", which is very invisible in the Bamboo, and I think it is a reason of confusion for some of the customers (BSP-5504, BSP-5492). This should be clear that to use "view issues in build result page" feature a user have to set up a project link for that particular plan(project) explicitly, in the project 'configuration' page (dashboard->all plans->project (not plan, not build)->application links.