Customisable {faded,trailing}-spinner icons

[eelcoj]

This allows to update the animated {faded,trailing}-spinner's stroke width. Useful to keep them in line with your app's aesthetic.

icon "faded-spinner", library: :animated, class: "stroke-2" # using Tailwind's stroke-width utility class

These have different widths now:

(left: stroke-2, right: stroke-4).

• Update README

[eelcoj]

Also open to ideas on how the animated dot-* could be customized (size of dots + spacing between them).