PLEASE DO NOT START THIS TASK

Currently, we customize the `ScaffolderPage` that lives in the App (packages/app/src/App.tsx) by changing the code.
The customizations are to add card groups (e.g. infrastructure and assessment) and to route the "Choose" button in the card to our "execute" route, instead of Scaffolder's one. See the `OrchestratorScaffolderTemplateCard` component (plugins/orchestrator/src/components/ScaffolderTemplateCard/OrchestratorScaffolderTemplateCard.tsx).

This is part of the old way to add a plugin to Janus Showcase.
However, changing the core Backstage code is not recommended now that we have dynamic plugins.
So we should create our version of the Create page, following the UX mockups, which is pretty much `ScaffolderPage`.

AFAIU we can't compose a new component from `ScaffolderPage` as we are doing for `OrchestratorScaffolderTemplateCard` because `ScaffolderPage` lives in the frontend plugin, i.e. we can't have a frontend plugin depending on another frontend plugin. 

This new component will replace the `ScaffolderPage` in the app-config when configuring the "/create" route.