[Assets] Display assets dimensions in assets list, grid and search views

[mattmultiplied]

It be helpful to display the dimensions of assets (primarily images) when viewing assets in list, grid and search views

In some cases we may have the same image in different dimensions intended to be used on different pages (see attached). With the current preview images you can't see they're different dimensions until you trial and error adding them into a page. This can be tedious in some cases if you're having to trial and error a fair few images.

Having the dimensions of the assets displayed will help us identify the image we want whether it's going in a card section, hero section, parallax section etc without having to do a bit of trial and error.