[server] Improve (repeated) Docker build times

Author: geropl

components/server/leeway.Dockerfile

@@ -3,14 +3,15 @@
 # See License.AGPL.txt in the project root for license information.
 
 FROM node:18.17.1-slim as builder
-COPY components-server--app /installer/
 
 # Install Python, make, gcc and g++ for node-gyp
 RUN apt-get update && \
     apt-get install -y python3 make gcc g++ && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/*
 
+COPY components-server--app /installer/
+
 WORKDIR /app
 RUN /installer/install.sh