✨(widgets) import widgets code from Messages and setup Docker workflow (#33)

This adds Gaufre v2 with source, documentation, examples and built artefacts.
Also includes the feedback widget from Messages.

README.md

@@ -3,8 +3,61 @@
 Repo containing code of:
 
 - [@gouvfr-lasuite/integration npm package](https://www.npmjs.com/package/@gouvfr-lasuite/integration) in [`packages/integration`](./packages/integration/)
+- Frontend widgets in [`packages/widgets`](./packages/widgets/)
 - [La Suite: integration docs and API](https://integration.lasuite.numerique.gouv.fr/) in [`website`](./website/)
 
+
+## Local development
+
+After checking out the repository, run:
+```
+$ make bootstrap
+```
+
+For both the website and the widgets projects, it will install dependencies, build, and start the development server, respectively at http://localhost:8930 and http://localhost:8931.
+
+To see dev server outputs, run:
+```
+$ make logs
+```
+
+You can view all available commands with:
+```
+$ make help
+```
+
+### Developing the website
+
+If you want a faster startup than `make bootstrap`, you can run more focused commands. For the website:
+
+```
+$ make website-start
+```
+
+This will start the development server at [http://localhost:8930](http://localhost:8930).
+
+### Developing Widgets
+
+We currently develop some embeddable widgets in the `packages/widgets` directory in this repository.
+
+```
+$ make widgets-start
+```
+
+This will start the development server at [http://localhost:8931](http://localhost:8931).
+
+You can then build them with:
+
+```
+$ make widgets-build
+```
+
+And deploy them to an S3 bucket, with `.aws/{config|credentials}` files in the root of the repository.
+```
+$ WIDGETS_S3_PATH=xxx make widgets-deploy
+```
+
+
 ## Licenses
 
 Source code is released under the [MIT](LICENSES/MIT.txt) and other