Fix odom velocity calculation and default QoS

[PGotzmann]

Summary:

Fixes Issue: #3, #4 Tested on: ROS2 galactic (gazebo simulation)

• transforms velocity to base_frame
• use the last tf transform instead of last x, y, yaw to calculate pose difference (easier transformation and handles angle normalization internally)
• provide angular velocity around z axis
• modifies default QoS of scan topic to SensorDataQoS and odom topic to SystemDefaultQoS to maximize compatibility