MR-1256 Review - Base UI component's initial strategy

Opens the way for creating the project's base UI components by setting up it's general strategy, implementing and spreading the initial Icon component.

• added babel's module resolver
• implemented Icon, IconCircled and IconButton components
• created the mapping file for centralizing the icon font strategy and sizing
• implemented the initial UI Token file
• replace most of the legacy components

There are a couple great topics to be discussed regarding the base components strategy, from the main simplification concept to naming and spacing. I've created a small draft with the reasoning behind the main decisions so we can discuss them and decide on the best path forward.

On the product side, the main goal is to reduce the visual and behavior inconsistencies. The Icon proportion/sizing comparison bellow do a good job highlighting that.

By better defining the props based on what currently exists on the UI we also have some gain on reduced feature components logic. Which also helps preventing the visual/behavior inconsistency conundrum.

Closes #3596 (closed) #3244 (closed)

Touches #3254 (closed)