Uninstall service task from project

Update project settings section responsible for managing service tasks to allow to uninstall already installed service tasks.

Uninstall should verify that given service task is not used by any of the processes in the project and if it is it should disallow uninstallation with proper warning displayed to end user.

Upon successful verification, uninstall should

• remove the work item definition file/entries for given service task
• remove maven dependency for given service task
• remove work item information from deployment descriptor for given service task