Sort package list in Dockerfiles

Sort the list of apt/zypper packages in Dockerfiles to make it obvious
where to insert new ones.

Change-Id: Ib1d890dbea88c009c067ffd8bc9cc9175979ed32

images/deckhand/Dockerfile.opensuse_15

@@ -31,23 +31,23 @@ EXPOSE $PORT
 RUN set -x && \
     zypper -q update -y && \
     zypper install -y --no-recommends \
-    git \
-    curl \
-    netcat-openbsd \
-    netcfg \
-    python3 \
-    python3-setuptools \
-    python3-pip \
-    python3-devel \
-    python3-python-dateutil \
-    python3-dbm \
     ca-certificates \
+    curl \
     gcc \
     gcc-c++ \
-    make \
+    git \
     libffi-devel \
     libopenssl-devel \
     libpqxx-devel \
+    make \
+    netcat-openbsd \
+    netcfg \
+    python3 \
+    python3-dbm \
+    python3-devel \
+    python3-pip \
+    python3-python-dateutil \
+    python3-setuptools \
     && zypper --non-interactive ar -f https://download.opensuse.org/repositories/devel:languages:python/openSUSE_Leap_15.1/devel:languages:python.repo \
     && zypper --non-interactive --gpg-auto-import-keys refresh devel_languages_python \
     && zypper --non-interactive install python3-six-1.11.0-lp151.3.1.noarch

images/deckhand/Dockerfile.ubuntu_bionic

@@ -32,22 +32,22 @@ EXPOSE $PORT
 RUN set -x && \
     apt-get -qq update && \
     apt-get -y install \
-    git \
-    curl \
-    netcat \
-    netbase \
-    python3 \
-    python3-setuptools \
-    python3-pip \
-    python3-dev \
-    python3-dateutil \
     ca-certificates \
-    gcc \
+    curl \
     g++ \
-    make \
+    gcc \
+    git \
     libffi-dev \
-    libssl-dev \
     libpq-dev \
+    libssl-dev \
+    make \
+    netbase \
+    netcat \
+    python3 \
+    python3-dateutil \
+    python3-dev \
+    python3-pip \
+    python3-setuptools \
     --no-install-recommends \
     && python3 -m pip install -U pip \
     && apt-get clean \

images/deckhand/Dockerfile.ubuntu_xenial

@@ -32,22 +32,22 @@ EXPOSE $PORT
 RUN set -x && \
     apt-get -qq update && \
     apt-get -y install \
-    git \
-    curl \
-    netcat \
-    netbase \
-    python3 \
-    python3-setuptools \
-    python3-pip \
-    python3-dev \
-    python3-dateutil \
     ca-certificates \
-    gcc \
+    curl \
     g++ \
-    make \
+    gcc \
+    git \
     libffi-dev \
-    libssl-dev \
     libpq-dev \
+    libssl-dev \
+    make \
+    netbase \
+    netcat \
+    python3 \
+    python3-dateutil \
+    python3-dev \
+    python3-pip \
+    python3-setuptools \
     --no-install-recommends \
     && python3 -m pip install -U pip \
     && apt-get clean \