Setup the foundation for Twenty UI library. (#4423)

* feat: create a separate package for twenty-ui, extract the pill component with hard-coded theme values into it, and use the component inside twenty-front to complete the setup

* feat: extract the light and the dark theme into twenty-ui and update the AppThemeProvider component inside twenty-front to consume themes from twenty-ui

* fix: create a decorator inside preview.tsx to provide a default theme to storybook development server

* fix: remove redundant type declarations and revert back the naming convention for theme declarations

* fix: introduce a default value for pill label within the story for development server

* fix: introduce the nx script into package.json for twenty-ui and resolve imports for theme type within the package

* fix: remove the pill component from the twenty-front package along with the story for it

* fix: revert the package versions to those before running the nx cli command for storybook init

* feat: update readme to include details for building the ui library and starting the storybook development server

* fix: include details about twenty-ui inside jest.config for twenty-front to complete front-jest job

* - Added preview head for font
- Added theme addon for light/dark switch
- Added ComponentDecorator

---------

Co-authored-by: Lucas Bordeau <bordeau.lucas@gmail.com>

packages/twenty-ui/.storybook/preview.tsx

@@ -0,0 +1,21 @@
+import { ThemeProvider } from '@emotion/react';
+import { withThemeFromJSXProvider } from '@storybook/addon-themes';
+import { Preview, ReactRenderer } from '@storybook/react';
+
+import { THEME_DARK, THEME_LIGHT } from '../src/theme/index';
+
+const preview: Preview = {
+  // TODO: Add toggle for darkTheme.
+  decorators: [
+    withThemeFromJSXProvider<ReactRenderer>({
+      themes: {
+        light: THEME_LIGHT,
+        dark: THEME_DARK,
+      },
+      defaultTheme: 'light',
+      Provider: ThemeProvider,
+    }),
+  ],
+};
+
+export default preview;