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

Start with the linked Figma specifications and confirm how the available design tokens map to the three versions: accordion list item, card item, and FAQ. Then inspect the library and Design System Toolbox app entry points to determine the required component, documentation, demos, and copyable customization code. Definition of Done is still unspecified, so clarify acceptance criteria before starting.