feat: expose modifications

[JasperSch]

It would be nice to expose the modified rows of the table.
This way applications writing custom logic to save the data can directly access them.
The returning object will likely change from:

list():
- result reactive modified version of data (saved)
- state reactive current state of the data (unsaved)
- selected reactive selected rows of the data (unsaved)

to

list():
- result reactive modified version of data (saved)
- state reactive current state of the data (unsaved)
- selected reactive selected rows of the data (unsaved)
- inserted reactive inserted rows (unsaved)
- edited reactive edited rows (unsaved)
- deleted reactive deleted rows (unsaved)

Open questions:

• Expose the saved or unsaved state or both?
• Preferred type of the exposed object? (Likely the same as state and result)
• Include rows with invalid edits with respect to foreign tables?