Make non-semantic icon color context-sensitive

## Component/pattern to amend

Icons
https://vanillaframework.io/docs/patterns/icons

## Visual






## Context

Sometimes we have a situation where we want to show that an item is a link (going back, external link) and to highlight the action I use the blue link colour for text and I want to align the icon that stands next to it. I think in these situations it would be beneficial to allow icons to be blue as well. Similarly sometimes I use icons as muted black for icons to establish hierarchy. I see customisation of icons is discouraged and potentially will be deprecated, I wanted to ask for reasoning and to rethink that decision.