Add Debian Jessie build image

This image is meant to be used to build packages for the Jessie release of Debian. See debian/nginx-build.

debian/jessie/setup.sh

@@ -12,7 +12,7 @@ curl -ssL -o /etc/apt/trusted.gpg.d/php.gpg https://packages.sury.org/php/apt.gp
 sh -c 'echo "deb https://packages.sury.org/php/ $(lsb_release -sc) main" > /etc/apt/sources.list.d/php.list'
 
 apt-get update
-apt-get -y --install-suggests install \
+apt-get -y install \
     git \
     dh-make \
     build-essential \
@@ -24,3 +24,6 @@ apt-get -y --install-suggests install \
     shellcheck \
     gnupg \
     libssl-dev
+
+apt-get clean
+rm -rf /var/lib/apt/lists/*