Typo in example usage of rlds dataset replayer, and missing example usage of recorder

[J-HowHuang]

Problem Description

In README.md

source install/setup.bash
ros2 run fogros2_rt_x replayer --ros-args -r dataset_name:=$DATASET_NAME 
# replace with yours, e.g. berkeley_fanuc_manipulation

instead of flag -r for remapping, should be -p for passing argument dataset_name

source install/setup.bash
ros2 run fogros2_rt_x replayer --ros-args -p dataset_name:=$DATASET_NAME 
# replace with yours, e.g. berkeley_fanuc_manipulation

Also, I thought the replayer was to used with ros2 bag record command. But @KeplerC told me it should be used with the recorder.

Suggestion

Update README.md:

Run the below commands to start recorder:

source install/setup.bash
ros2 run fogros2_rt_x recorder --ros-args -p dataset_name:=$DATASET_NAME 
# replace with yours, e.g. berkeley_fanuc_manipulation

In the other shell, run replayer to replay your dataset

ros2 run fogros2_rt_x replayer --ros-args -p dataset_name:=$DATASET_NAME 
# replace with yours, e.g. berkeley_fanuc_manipulation

The result ros bag will be stored under ./rosbags/$DATASET_NAME