fix: add liberation fonts to Docker image and configure resvg to use them for label rendering

paperless-backend/Dockerfile

@@ -8,7 +8,7 @@ RUN npm run build
 
 # Production
 FROM node:20-alpine
-RUN apk add --no-cache ghostscript imagemagick
+RUN apk add --no-cache ghostscript imagemagick font-liberation fontconfig
 WORKDIR /app
 COPY --from=builder /app/dist ./dist
 COPY --from=builder /app/node_modules ./node_modules