Split these layers up

Currently it's creating a 2.5GB layer, which takes ages to download
and extract. Also Chrome updates much more regularly than the other
packages.

docker/Dockerfile.base

@@ -12,21 +12,21 @@ COPY pyproject.toml poetry.lock /app/
 # doesn't confuse poetry.
 ENV POETRY_VIRTUALENVS_IN_PROJECT=false
 
-# All the X11 packages are required for chromium/playwright which we use for
-# generating PDFs.
-#
 # It would be nice to be able to build an image without build tools and dev
 # packages, however this complicates upgrading packages which require compilation.
 RUN apt-get update && \
     apt-get install -y --no-install-recommends \
       libxml2-dev libxslt1-dev libffi-dev git glpk-utils \
       postgresql-client make build-essential libpq-dev \
-      libx11-xcb1 libxcomposite1 libxss1 \
-      libxcursor1 libxdamage1 libxi6 libxtst6 libnss3 libcups2 \
-      libxrandr2 libasound2 libatk1.0-0 libatk-bridge2.0-0 libgtk-3-0 libzbar0 \
-      coinor-cbc curl && \
-    pip3 install poetry==1.7.1 && \
-    poetry install && \
-    poetry run playwright install-deps && \
-    poetry run playwright install chromium && \
+      libzbar0 coinor-cbc curl && \
     rm -rf /var/lib/apt/lists/*
+
+RUN pip3 install poetry==1.7.1 && \
+    poetry install
+
+RUN poetry run playwright install-deps && \
+    rm -rf /var/lib/apt/lists/*
+
+RUN poetry run playwright install chromium && \
+    rm -rf /var/lib/apt/lists/*
+