Remove outdated translated documentation and add a Translate button (#278)

Author: ClementPasteau

CONTRIBUTE.md

@@ -27,15 +27,15 @@ First install:
 Run:
 
 ```sh
-poetry install
+poetry install --no-root
 ```
 
 ### Run the project
 
 ```sh
-mkdocs serve
+poetry run mkdocs serve
 # Or, for faster reload after changes:
-mkdocs serve --dirtyreload
+poetry run mkdocs serve --dirtyreload
 ```
 
 This will run the documentation on http://localhost:8000.

README.md

@@ -6,7 +6,7 @@ This repository holds [the official documentation](https://wiki.gdevelop.io) for
 
 ## Getting Started
 
-| ❔ I want to...                              | 🚀 What to do                                                                     |
-| -------------------------------------------- | --------------------------------------------------------------------------------- |
-| Improve or add articles to the documentation | Head over to [this README](./SYNTAX.md) to understand the syntax of the documentation.|
-| Bring improvements to the documentation interface | Head over to [this README](./CONTRIBUTE.md) to understand how this repository works. |
+| ❔ I want to...                                   | 🚀 What to do                                                                          |
+| ------------------------------------------------- | -------------------------------------------------------------------------------------- |
+| Improve or add articles to the documentation      | Head over to [this README](./SYNTAX.md) to understand the syntax of the documentation. |
+| Bring improvements to the documentation interface | Head over to [this README](./CONTRIBUTE.md) to understand how this repository works.   |