osbuilder: move code into tools directory

move all osbuilder files into `tools` directory to be able
to merge this into kata-containers repo.

Signed-off-by: Salvador Fuentes <salvador.fuentes@intel.com>

tools/osbuilder/rootfs-builder/debian/Dockerfile-aarch64.in

@@ -0,0 +1,35 @@
+#
+# Copyright (c) 2020 ARM Limited
+#
+# SPDX-License-Identifier: Apache-2.0
+
+# NOTE: OS_VERSION is set according to config.sh
+from docker.io/debian:@OS_VERSION@
+
+# RUN commands
+RUN apt-get update && apt-get install -y \
+    autoconf \
+    automake \
+    binutils \
+    build-essential \
+    chrony \
+    cmake \
+    coreutils \
+    curl \
+    debianutils \
+    debootstrap \
+    g++ \
+    gcc \
+    git \
+    libc-dev \
+    libstdc++-6-dev \
+    m4 \
+    make \
+    sed \
+    systemd \
+    tar \
+    vim
+# This will install the proper golang to build Kata components
+@INSTALL_GO@
+@INSTALL_MUSL@
+@INSTALL_RUST@

tools/osbuilder/rootfs-builder/debian/Dockerfile.in

@@ -0,0 +1,41 @@
+#
+# Copyright (c) 2018 SUSE
+#
+# SPDX-License-Identifier: Apache-2.0
+
+# NOTE: OS_VERSION is set according to config.sh
+from docker.io/debian:@OS_VERSION@
+
+# RUN commands
+RUN apt-get update && apt-get --no-install-recommends install -y \
+    apt-utils \
+    autoconf \
+    automake \
+    binutils \
+    build-essential \
+    ca-certificates \
+    chrony \
+    cmake \
+    coreutils \
+    curl \
+    debianutils \
+    debootstrap \
+    g++ \
+    gcc \
+    git \
+    libc-dev \
+    libstdc++-6-dev \
+    m4 \
+    make \
+    musl \
+    musl-dev \
+    musl-tools \
+    sed \
+    systemd \
+    tar \
+    vim \
+    wget
+
+# This will install the proper golang to build Kata components
+@INSTALL_GO@
+@INSTALL_RUST@

tools/osbuilder/rootfs-builder/debian/config.sh

@@ -0,0 +1,20 @@
+#
+# Copyright (c) 2018 SUSE
+#
+# SPDX-License-Identifier: Apache-2.0
+
+OS_VERSION=${OS_VERSION:-9.5}
+
+# Set OS_NAME to the desired debian "codename"
+OS_NAME=${OS_NAME:-"stretch"}
+
+PACKAGES="systemd iptables init chrony kmod"
+
+# NOTE: Re-using ubuntu rootfs configuration, see 'ubuntu' folder for full content.
+source $script_dir/ubuntu/$CONFIG_SH
+
+# Init process must be one of {systemd,kata-agent}
+INIT_PROCESS=systemd
+# List of zero or more architectures to exclude from build,
+# as reported by  `uname -m`
+ARCH_EXCLUDE_LIST=()

tools/osbuilder/rootfs-builder/debian/rootfs_lib.sh

@@ -0,0 +1,7 @@
+#
+# Copyright (c) 2018 SUSE
+#
+# SPDX-License-Identifier: Apache-2.0
+
+# NOTE: Re-using ubuntu rootfs lib, see 'ubuntu' folder for details.
+source ${script_dir}/ubuntu/$LIB_SH