🏗️(core) migrate from pip to uv

We want to migrate our projects from pip to uv to take the benefits of
the lock file and have reproducible installations.
A first uv.lock file is comitted and the Dockerfile and compose are
modified to work with uv

docker-compose.yml

@@ -42,6 +42,7 @@ services:
       - ./src/backend:/app
       - ./data/media:/data/media
       - ./data/static:/data/static
+      - /app/.venv
     depends_on:
       postgresql:
         condition: service_healthy
@@ -117,6 +118,7 @@ services:
       - ./src/backend:/app
       - ./data/media:/data/media
       - ./data/static:/data/static
+      - /app/.venv
     depends_on:
       postgresql:
         condition: service_healthy