Add icon button toggle usage

Problem

Based on this use case, there was a need for a more simplified method for toggling a locked state on a list of features. The problem is there was an additional column dedicated to UI for locking/unlocking features, when it could have been as simple as a toggling icon button next to the label.

Solution

This adds guidelines for this type of interaction and should simplify a lot of cases where we are using multiple dropdowns and toggles where we could be using something as simple as an icon button toggle.

Future scope

Possibly explore an icon toggle feature for gl-button, if needed.