As proposed in T95802, this adds buttons to modify the override in the
the library override display mode.
I decided to add the right column so that the left column can be
scrolled independently, like we do it for the restriction toggles in
other display modes{F12901085} Some further usability improvements are planned.
I decided to add the right column so that the left column can be scrolled independently, like we do it for the restriction toggles in other display modes. This differs from the Data API mode, [[ https://developer.blender.org/T95802#1314065 | which has some issues ]] in my opinion.
Contains some cleanups that are to be committed separately, just uploading it all as one patch for some quick review.