Serve CSS dependencies from local webserver

Privacy improvement.

Dockerfile

@@ -2,17 +2,19 @@ FROM python:3.8-alpine
 
 RUN adduser -S fabcal
 
-RUN apk add --no-cache build-base libuv-dev libffi-dev && \
-    pip3 install poetry
+RUN apk add --no-cache build-base libuv-dev libffi-dev yarn && \
+    pip3 install -U poetry
+
+RUN install -d -o fabcal /app
 
 USER fabcal
 
-COPY poetry.lock pyproject.toml /app/
+COPY poetry.lock pyproject.toml package.json yarn.lock /app/
 
 WORKDIR /app/
 
-RUN pip install -U poetry && \
-    poetry install --only main
+RUN poetry install --only main && \
+    yarn install
 
 COPY fabcal /app/fabcal/
 COPY static/ /app/static/