bug#54905: Allow in tabulated lists to resize columns with the mouse

[Kiss Dénes]

I'm not a fan of using the mouse in general, but when during browsing tables you want to resize columns, it is more natural to grab some handle with the mouse at the edge of the column and drag to resize it, than doing it from the keyboard.

It is the norm in GUI table apps, so it would be great if emacs could also provide a way to do it, e.g. by putting some graphical handle character after the column name which could be grabbed and dragged with the mouse to change column size.