Add `IntegerSemanticsConstraint`

Overview

Over a year ago, XB added StringSemanticsConstraint. Because URLs, titles, names of people, filenames and so on all are strings, but they're NOT all the same kind of string.

This is coming up again for integers over at https://git.drupalcode.org/project/experience_builder/-/merge_requests/1..., for video width/height:

🐛 This width↝entity␜␜entity:file␝filesize␞␟value is nonsense ("filesize" is assigned as width). Same for height↝entity␜␜entity:file␝created␞␟value ("created" UNIX timestamp is assigned as height).

Proposed resolution

Introduce IntegerSemanticsConstraint.

User interface changes

None — except that if DynamicPropSource suggestions are visible, they will now make a lot more sense.