[add] Python client packaging first draft

client/README.md

@@ -0,0 +1,28 @@
+# Ethereum app Python client
+
+This package allows to communicate with the Ethereum application, either on a
+real device, or emulated on Speculos.
+
+## Installation
+
+This package is deployed:
+
+- on `pypi.org` for the stable version. This version will work with the
+  application available on the `master` branch.
+  ```bash
+  pip install ledger_app_clients.ethereum`
+  ```
+- on `test.pypi.org` for the rolling release. This verison will work with the
+  application code on the `develop` branch.
+  ```bash
+  pip install --extra-index-url https://test.pypi.org/simple/ ledger_app_clients.ethereum`
+  ```
+
+### Installation from sources
+
+You can install the client from this repo:
+
+```bash
+cd client/
+pip install .
+```