Refactor task creation / edit process

[codeliner]

• Creating a task should always start with choosing a connector
• The task configuration is delegated to the connector tag
  • The process manager should only provide communication methods:
  • get previous task
  • get all tasks
  • get/set task type
  • get/set ginger type
  • get/set metadata
  • get task group (including finally tasks of the group)
  • add new task to group with priority (1 - 49 || 51 - 99)
  • add new task to finally group with priority (100 - 199)
  • remove task (only allowed for tasks of the same task group and not for the current one)
• The process manager is responsible for the actions:
  • create, update, delete main task
  • reorder tasks