Add Spectre Components

Add "Components" from Spectre, stories and tests for them:

* ~~Accordions~~
* Autocomplete
* ~~Avatars~~
* Badges
* Bars
* Breadcrumbs
* ~~Cards~~
* ~~Chips~~
* Empty states
* Menus
* ~~Modals~~
* ~~Navs~~
* Pagination
* Panels
* ~~Popovers~~
* Steps
* Tabs
* ~~Tiles~~
* Toasts
* Tooltips

1. Create an issue "Add component {ComponentName}" and state that you're working on it.

2. Follow the same code style as other components:
* Use Standard JS style
* Use component layout described in the readme and as seen in other component files

3. Make a pull request following the [PR template](https://github.com/CodeDraken/spectre-react/blob/master/PULL_REQUEST_TEMPLATE.md) and add a reference to the issue.

https://picturepan2.github.io/spectre/components.html

Commencez par lire le README du dépôt et examiner les fichiers de composants existants afin de comprendre la mise en page et le style Standard JS. Choisissez un composant Spectre non terminé, créez son issue séparée comme demandé, puis ajoutez le composant, les stories et les tests, et utilisez le modèle de PR lors de la soumission de la pull request.

Rédigé par le modèle d'indexation à partir du texte de l'issue.