In `library`, add `accordion` component

Description

As a user of the OUDS library
I want to be able to use the component
So that I can add this OUDS component in my own projects

As a user of the library
I want to be able to use the component
So that I have access to the documentation on how to use it

As a user of the Design System Toolbox app
I want to access the Component
So that I can understand how to use it:

• while using the demo app I can interact with the available options and observe the changes on the component itself
• I can see the code associated to the component customization
• I can copy and paste the code from the app based on the selected customization
• or when looking into the code of the app itself, I would also understand how to use it

Context

Verbatims from @MaximeTonnerre:

The "Accordion » components is ready on the design side.
The corresponding design tokens will be included in version 2.6 of the design token library.
 
Technically, the component is split into three separate versions:
- Accordion list item
- Accordion card item
- Accordion FAQ

See Figma specifications

Definition of Ready

• Have Figma specifications available
• Have tokens available

Definition of Done

To be defined

No files or tests are named. Start by comparing existing OUDS library components and the Design System Toolbox app, then consult the linked Figma specifications and available design tokens; done should be defined for the accordion list item, card item, FAQ variant, documentation, and interactive demo.