Inserting an image into a document does not trigger autosave

[s-blu]

Describe the bug
When inserting a image into a document, no autosave is triggered. That can lead to data loss, if no other action is performed and the app closed.

Which part of the application is affected?
Documents

To Reproduce
How is this problem reproduceable? Please describe needed steps to encounter the behavior:

1. Open up a document
2. Insert a image
3. Close the application (navigating away from the document triggers the on blur save)

Expected behavior
It should obviously autosave.

Version
0.9.0-SNAPSHOT