Add README.md for Catena4450_test01.ino

[terrillmoore]

Every sketch needs a README.md explaining (at a minimum):

• what the sketch is intended to do, and when to use it
• which Catenas are supported
• what external hardware is required, and what external hardware is optionally supported
• what libraries are needed
  • how to set up libraries using git-boot.sh (if using git-boot.sh)
  • how to set up libraries from the Arduino environment (if using the environment)
• data format (pointing to extras and the appropriate docs)
• how to provision (pointing to the general instructions) plus any info about platform GUIDs
• how to verify that it's working