Removes two IMU launch files. They are not used by other
stretch_ros code, and they appear to not function properly.
For example, they do not appear to use a proper tf frame for
the IMU, can produce problematic tf trees, and can result
in tf query timing problems.

The ROS Noetic Respeaker package did not function as expected.
For now, I'm removing this launch file that depends on it.

I tried and failed to use the following version:

$ apt show ros-noetic-respeaker-ros
Package: ros-noetic-respeaker-ros
Version: 2.1.21-2focal.20210424.002454
Priority: optional
Section: misc
Maintainer: Yuki Furuta <furushchev@jsk.imi.i.u-tokyo.ac.jp>
Installed-Size: 153 kB
Depends: flac, ros-noetic-angles, ros-noetic-audio-common-msgs, ros-noetic-dynamic-reconfigure, ros-noetic-geometry-msgs, ros-noetic-std-msgs, ros-noetic-tf
Download-Size: 20.8 kB
APT-Manual-Installed: yes
APT-Sources: http://packages.ros.org/ros/ubuntu focal/main amd64 Packages
Description: The respeaker_ros package

Node that outputs d435i frustums now works with ROS Noetic, etc.
I've also added a new launch file to more easily test and
visualize the frustums. It has an associated rviz configuration
file.

+ Users may define out-of-range goals intentionally if they want to move any joint to its limit without knowing the joint's calibrated limit for a specific robot

Apparently, upstream RealSense changes in ROS Melodic broke Stretch URDF creation. More information about the changes can be found using the following information:

+ realsense-ros release: https://github.com/IntelRealSense/realsense-ros/releases/tag/2.2.14
+ Debian package: ros-melodic-realsense2-description/bionic,now 2.2.14-1bionic.20200630.141906
+ relevant commit: f7cd5fced5

The corrected issue has to do with changes to "use_nominal_extrinsics" specified in the D435i xacros in the realsense2_description package.

The current commmit also changes the d435i launch file for Stretch (d435i_basic.launch) so that it no longer performs "initial_reset" by default. "initial_reset" appears to have resulted in long delays and freezing when bringing up the camera on the robot.

An excerpt from Intel's documentation for initial_reset follows:

"initial_reset: On occasions the device was not closed properly and due to firmware issues needs to reset. If set to true, the device will reset prior to usage." from https://github.com/intel-ros/realsense