Remove append/prepend utility classes
Description
In common.scss we have some very old append and prepend utility CSS classes, which are inconsistent with our design system.
We should prefer using the very cool gitlab ui utility classes. Here's the latest utilities.scss file which contains a full list of the utility classes available.
Proposal
Let's remove and replace what references we can
Guidance - Some classes use values outside the design system
The biggest issue with deprecating these, however is that some spacings are not replicated in our design system (e.g.
5px). My preference is to suggest that developers push back on designs that require these values, but that seems like a big choice to be made on preferences.
Edited by Paul Slaughter