SW-4993: Reduce the publish rate of imu tf transforms

[Samahu]

Related Issues & PRs

• closes High TF Broadcast Rate #105
• related Ouster Time Handling for tf and sensor msgs  #9

Summary of Changes

• Reduce the publish rate of tf transforms by publishing IMU TF transforms at the same rate as LIDAR TF transforms

Note:
Using StaticTransformPublisher is the proper thing to do but due to an issue that exists(or existed) in ROS1 which causes it to generate tons of warnings that couldn't be silenced as noted in #9 and also based on my own experience; so as a compromise I kept everything pretty much as is but reduced the publish rate of IMU TF transforms by publishing them at the same time as LIDAR TF transforms.

Validation

• Before this change the total publish rate of TF messages generated by ROS driver would be at 120+ Hz.
• Launch a sensor with the ouster driver in one terminal and run a tf monitor in another terminal and observe the frequency of published TF transforms. The total publish rate shouldn't exceed 20 Hz for lidar modes with 10 Hz FPS and 40 Hz for lidar modes with 20 Hz FPS.