Add a draggable list builder for content entities

Updated for the latest core change. Leaving at RTBC because the integration parts (almost*) didn't change.

* I just had to add the access check to the entity query.

I couldn't get #13 to apply (just like the bot, I guess), so I started from #11, and just fixed up the info file change manually.

Hmm... the DrupalCI setup still uses a too old PHP version for the int|float typehint, so I thought I'd try an MR instead, but I guess Gitlab CI is not set up yet either. So will need some maintainer action at least if we want to see this "officially" pass tests. Leaving at RTBC, though, because the patch itself is fine, as far as I can tell. (And I did try it out locally, at least...)

Note that the core issue has been committed now. 🎉️

Still makes sense for the patch/MR to be committed as is, as the new trait wil only be in 10.3 but that should hopefully alleviate any concerns of the long-term maintenance burden.

Rebased the MR for 🐛 EntityViewsData Column information not available for computed entity reference fields Fixed