Adding support for stereo input (ROS2)

[mirellameelo]

Hi. The changes are the following:

• adding the support for stereo input (ROS2)
• using ROS simulation time instead of system time
• printing msgs with RCLCPP_INFO instead of std::cout
• changing the publisher's topic to match with the subscriber's topic.

[SteveMacenski]

LGTM, there's some formatting issues but those exist before you

[SteveMacenski]

I'm not an admin here, but LGTM on the first-order level, #38 obviously has some more steps in it but this seems like a very reasonable first one

[ymd-stella]

Please apply clang-format.
I often use the following command.

DIRS_TO_EXCLUDE=".git 3rd cmake docs build .idea cmake-build-debug cmake-build-release"
for DIR in ${DIRS_TO_EXCLUDE}; do
    EXCLUDE_CMD="${EXCLUDE_CMD} -type d -name ${DIR} -prune -o"
done
FILES=$(find . ${EXCLUDE_CMD} -type f -regex ".*\.\(c\|h\|cc\|hh\|cpp\|hpp\)" -print)
for FILE in ${FILES}; do
    clang-format-6.0 -style=file -i ${FILE}
done