ROS Node Integration

[Jmeyer1292]

This PR:

• moves the stand-alone keyence library into a subdirectory (much like moveit structures its code).
• Implements a ROS node that queries the Keyence controller at the program configured rate for more sensor data.
• Adds a ROS service that allows for remote changing of the active program (e.g. to turn the sensor off).
• Adds a new GetSettings command to the keyence library that is used to fetch info about the active program for use in the ROS node.

The ROS side of things based on previous work for the Godel project done by @gavanderhoorn and Matthew West.

@Levi-Armstrong You looked at my last PR, would you be so kind to do this one too?

[Jmeyer1292]

@Levi-Armstrong I have:

• Updated the readme to better reflect the new state of the code
• Moved a lot of constants into the settings header (and they even have comments)
• Improved some of the error handling