HaikuDepot: Remove Custom List

Further removal of the use of custom list class;
this time with the generic undo functionality.

Relates To #15534

Change-Id: I804a31abc07f42f4f1695562b6f948feb465db0c
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3739
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

HaikuDepot: Base-classes for generic undo/redo support.

I plan to use these in the text view and editor framework.

HaikuDepot: Base-classes for generic undo/redo support.

I plan to use these in the text view and editor framework.