[misc] integrate git-bridge with overleaf dev-env and prod setup

- Add `base` target for dev-env
- Add `node` user for dev-env and prod
- Use `make` all the way

services/git-bridge/.dockerignore

@@ -2,4 +2,5 @@
 !/lib
 !/src/main
 !/pom.xml
+!/Makefile
 !/LICENSE

services/git-bridge/Dockerfile

@@ -1,11 +1,18 @@
 # Dockerfile for git-bridge
 
-FROM maven:3-jdk-8
+FROM maven:3-jdk-8 as base
+
+RUN apt-get update && apt-get install -y make \
+ && rm -rf /var/lib/apt/lists
+
+RUN useradd --create-home node
+
+FROM base as builder
 
 WORKDIR /app
 
 COPY . /app
-RUN mvn clean package \
+RUN make package \
 # The name of the created jar contains the current version tag.
 # Rename it to a static path that can be used for copying.
 &&  find /app/target \
@@ -14,15 +21,14 @@ RUN mvn clean package \
 
 FROM openjdk:8-jre
 
-RUN apt-get update \
- && apt-get install --no-install-recommends -y \
-      git \
- && rm -rf \
-      /var/lib/apt/lists/*
+RUN apt-get update && apt-get install -y git \
+ && rm -rf /var/lib/apt/lists
 
-USER www-data
+RUN useradd --create-home node
 
 ENTRYPOINT ["java", "-jar", "/git-bridge.jar"]
 CMD ["/conf/runtime.json"]
 
-COPY --from=0 /git-bridge.jar /
+COPY --from=builder /git-bridge.jar /
+
+USER node