Feature/hello discover devices

[hello-fazil]

This PR introduces the new tool REx_discover_hello_devices.py.

• This tool will enable users to find and map all the robot-specific USB devices (i.e. Lift, Arm, Left wheel, Right wheel, Head, Wrist/End-of-arm) and assign them to the robot by updating UDEV rules and stretch configuration files.
• This tool prompts the users to move the robot manually in a specific manner, and based on the joint movements, the hello-* device assignments are done. This tool supports stretch_gripper and stretch_dex_wrist tool configurations.
• This tool can be recommended to users every time a PCBA, or motor assembly is replaced or when any /dev/hello-* devices go missing from the USB bus for debugging.

Usage

For use with S T R E T C H (R) RESEARCH EDITION from Hello Robot Inc.
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usage: REx_discover_hello_devices.py [-h] [--discover | --list_tty]

Find and map all the robot-specific USB devices (i.e. Lift, Arm, Left wheel, Right wheel, Head, Wrist/End-of-arm) and assign them to
the robot by updating the UDEV rules and stretch configuration files.This tool can be utilized everytime a PCBA, motor assembly is
replaced or if any /dev/hello-* devices go missing from the USB bus.

optional arguments:
  -h, --help  show this help message and exit
  --discover  Discover the devices by set of user instructions and re-assign them to the robot
  --list_tty  Display the currently available devices info(model,path,serial,vendor) in the paths /dev/ttyACM* and /dev/ttyUSB*

cmd : REx_discover_hello_devices.py --discover Example output

[hello-binit]

Good idea! Looks good to merge. I'd add an entry to the CHANGELOG to document that a new tool was added.