Add a ROS 2 node for serial MSCKF processing of ROS 2 bags

[0xWILL225]

This change adds the node ov_msckf/src/ros2_serial_msckf.cpp in ov_msckf, a ROS 2 equivalent to the existing ros1_serial_msckf, for processing ROS 2 bags. ov_eval/src/pose_to_file_ros2.cpp is added as an equivalent to ov_eval/src/pose_to_file.cpp, migrated to ROS 2, which fulfills an existing TODO. Changes were made to ov_eval/src/utils/Recorder.h to make it compatible with both ROS 1 and 2.

I've also added scripts equivalent to run_ros_eth.sh and run_ros_uzhfpv.sh that use the added ROS 2 launch files instead of the existing ROS 1 ones to process all datasets in the EuRoC MAV and UZH-FPV collections. The scripts utilize environment variables instead of hard-coded paths. The newly added launch file ov_msckf/launch/serial.launch.py supports debugging the node with gdb.

I have tested the changes in a ROS 2 Humble Ubuntu 22.04 docker environment and verified that it works as expected on the EuRoC MAV datasets.