Implement autosave of bpmn

[standeren]

Description

Implementation of configuration options in the config-panel in the process-editor relies on the bpmn file to be autosaved when tasks are dragged in and out of the diagram to ensure that it exists a corresponding layoutset to the task to configure when this should be possible.

Since there are some operations in backend that need to finish before we can continue editing related to the task-id-syncing and changing of folderstructure when adding and removing tasks/layoutsets, we need to disable editing until the response has returned OK, f.ex. by implementing a spinner.

Additional information

This issue should also include doing the calls to addLayoutSet, deleteLayoutSet and potentially updateLayoutSet if that becomes relevant. With this implementation also comes the need to implement a confirmation dialoge when deleting a task that tells the user that this will also include deleting the connected layoutset and all its layouts.