Background

Originally set out as useful middle-step to provide a longer time compatibility layer with OOUI and derived interfaces, we've set out to provide a huge number of deprecated tokens in Codex. Those would be fed into WikimediaUI Base and provide a (through this extra leg) single source of truth.
When starting to replace deprecated values, specifically in the group where no 1:1 token values where available in T331403, it became clear that the amount of time needed to immediately use the new token names, is certainly the faster way than to work in two step approach.
It also became clearer within first implementations, that the deprecated tokens, even though clearly marked, make it into new products. For best designer/developer experience we moved along getting rid of WikimediaUI Base compatibility layer.
It still makes understanding the replacement patches much simpler and helps in the code reviews. So it wasn't lost work.

Goal

Remove the deprecation layer, resulting in 'deprecated-aliases-wikimedia-ui-base' files from Codex after the code replacements in T334934 are successfully resolved.
Public code snippet of last v1.2.0: https://phabricator.wikimedia.org/P54580

Acceptance criteria

• No deprecated alias token file is generated any more and the code responsible for it has been removed.