Install build dependencies from build.sh

Instead of repeating the build dependencies in both Dockerfile-files,
let us install them from `build.sh`.

Dockerfile-bullseye

 FROM debian:bullseye
-RUN apt-get update && apt-get -y upgrade
-RUN apt-get install -y git curl build-essential debhelper dh-autoreconf autotools-dev libssl-dev nettle-dev docbook2x lsb-release
 WORKDIR /root/
 COPY build.sh build.sh
 RUN ./build.sh

Dockerfile-buster

 FROM debian:buster
-RUN apt-get update && apt-get -y upgrade
-RUN apt-get install -y git curl build-essential debhelper dh-autoreconf autotools-dev libssl-dev nettle-dev docbook2x lsb-release
 WORKDIR /root/
 COPY build.sh build.sh
 RUN ./build.sh

build.sh

@@ -8,6 +8,23 @@ pwd
 cd /root
 ls -ld .
 
+# Install required build dependencies
+apt-get update
+apt-get -y upgrade
+apt-get install -y \
+  autotools-dev \
+  build-essential \
+  curl \
+  debhelper \
+  dh-autoreconf \
+  docbook2x \
+  git \
+  libssl-dev \
+  lsb-release \
+  nettle-dev \
+  --
+
+
 lsb_release_name=$(lsb_release -sc)
 
 package="radsecproxy"