docker: try to reduce image size

docker/dev/django/Dockerfile

@@ -1,47 +1,35 @@
-# pull official base image
-FROM python:3.11-slim-buster AS python
-LABEL authors="Herculino de Miranda Trotta"
+FROM python:3.11-slim-buster AS python-build-stage
 
-FROM docker.io/python AS python-build-stage
+RUN apt-get update && apt-get install --no-install-recommends -y \
+    build-essential \
+    gettext \
+    libpq-dev \
+    && rm -rf /var/lib/apt/lists/*
 
-RUN apt update && apt install --no-install-recommends -y \
-  # dependencies for building Python packages \
-  build-essential \
-  # psycopg2 dependencies \
-  gettext \
-  libpq-dev
-
-# Requirements are installed here to ensure they will be cached.
 COPY ../requirements.txt .
+RUN pip wheel --wheel-dir /usr/src/app/wheels -r requirements.txt
 
-# Create Python Dependency and Sub-Dependency Wheels.
-RUN pip wheel --wheel-dir /usr/src/app/wheels  \
-  -r requirements.txt
+FROM python:3.11-slim-buster AS python-run-stage
 
-
-FROM docker.io/python AS python-run-stage
-#COPY --from=webpack_build /usr/src/frontend/build /usr/src/frontend/build
-
-# set work directory
 WORKDIR /usr/src/app
 
-# set environment variables
-ENV PYTHONDONTWRITEBYTECODE 1
-ENV PYTHONUNBUFFERED 1
+ENV PYTHONDONTWRITEBYTECODE=1 \
+    PYTHONUNBUFFERED=1
 
-COPY --from=python-build-stage /usr/src/app/wheels  /wheels/
-RUN apt update && apt install --no-install-recommends -y gettext
-RUN pip install --upgrade pip
-RUN pip install --no-cache-dir --no-index --find-links=/wheels/ /wheels/* \
-  && rm -rf /wheels/
+COPY --from=python-build-stage /usr/src/app/wheels /wheels/
+
+RUN apt-get update && \
+    apt-get install --no-install-recommends -y gettext && \
+    rm -rf /var/lib/apt/lists/* && \
+    pip install --upgrade pip && \
+    pip install --no-cache-dir --no-index --find-links=/wheels/ /wheels/* && \
+    rm -rf /wheels/ ~/.cache/pip/*
 
 COPY ./docker/dev/django/start /start
-RUN sed -i 's/\r$//g' /start
-RUN chmod +x /start
-
 COPY ./docker/dev/procrastinate/start /start-procrastinate
-RUN sed -i 's/\r$//g' /start-procrastinate
-RUN chmod +x /start-procrastinate
+RUN sed -i 's/\r$//g' /start && \
+    chmod +x /start && \
+    sed -i 's/\r$//g' /start-procrastinate && \
+    chmod +x /start-procrastinate
 
-# copy project
 COPY ./app .