Using new husarnet/ros image with a better support for SHM host<>docker communication

[DominikN]

1. Using a new husarnet/ros base image with a new ros_entrypoint.sh template:

#!/bin/bash
set -e

output=$(husarnet-dds singleshot) || true
if [[ "$HUSARNET_DDS_DEBUG" == "TRUE" ]]; then
  echo "$output"
fi

# setup ros environment
source "/opt/ros/$ROS_DISTRO/setup.bash"
test -f "/ros2_ws/install/setup.bash" && source "/ros2_ws/install/setup.bash"

if [ -z "$USER" ]; then
    export USER=root
elif ! id "$USER" &>/dev/null; then
    useradd -ms /bin/bash "$USER"
fi

# <additional-user-commands>

if [ $# -eq 0 ]; then
    exec gosu $USER /bin/bash
else
    exec gosu $USER "$@"
fi

This template allows running the container as a different user (specified with USER env). Thanks to that the shm communication setup between the container and a host is simpler. # <additional-user-commands> allows you to easily inject e.g. the lauching of the ROS 2 node for healthcheck bringup (as in this PR).

2. Using a new rosbot_ros ROS 2 package (v0.12.0) with a firmware providing the hardware STM32 CPU ID over the /get_cpu_id service. Moreover this firmware introduces the new mechanism of selecting the serial interface over which it's trying to reach the Micro ROS Agent (FTDI or SBC pinout)