add conditional Interface import + app factory

src/__init_.py

@@ -0,0 +1,10 @@
+from yunohost.interface import Interface
+
+from yunohost.user import app as user_app
+
+
+def create_interface():
+    app = Interface(root=True)
+    app.add(user_app)
+
+    return app.instance

src/interface/__init__.py

@@ -0,0 +1,6 @@
+import os
+
+if os.environ.get("INTERFACE", "cli") == "cli":
+    from yunohost.interface.cli import Interface  # noqa
+else:
+    from yunohost.interface.api import Interface  # noqa