move dependencies into 'dependencies' layer to speed up build time

Dockerfile

@@ -1,9 +1,8 @@
 # Use an official Node runtime as the base image
-FROM node:18
-ARG GIT_COMMIT=unknown
-ENV GIT_COMMIT=$GIT_COMMIT
+FROM node:18 AS base
 
-# Install Nginx, Supervisor, Git, jq, curl, and Node Exporter dependencies
+# Create dependency layer
+FROM base AS dependencies
 RUN apt-get update && apt-get install -y \
     nginx \
     supervisor \
@@ -11,15 +10,21 @@ RUN apt-get update && apt-get install -y \
     curl \
     jq \
     wget \
+    apache2-utils \
     && rm -rf /var/lib/apt/lists/*
 
-# Install cloudflared
 RUN curl -L https://github.com/cloudflare/cloudflared/releases/latest/download/cloudflared-linux-amd64.deb > cloudflared.deb \
     && dpkg -i cloudflared.deb \
     && rm cloudflared.deb
 
-# Install apache2-utils
-RUN apt-get update && apt-get install -y apache2-utils
+# Final image
+FROM base
+
+# Copy installed packages from dependencies stage
+COPY --from=dependencies / /
+
+ARG GIT_COMMIT=unknown
+ENV GIT_COMMIT=$GIT_COMMIT
 
 # Set the working directory in the container
 WORKDIR /usr/src/app
@@ -39,7 +44,7 @@ COPY . .
 RUN npm run build-prod
 
 # So we can see which commit was used to build the container
-# openfront.io/commit.txt
+# https://openfront.io/commit.txt
 RUN echo $GIT_COMMIT > static/commit.txt
 
 # Copy Nginx configuration and ensure it's used instead of the default