message: Adding contract building step to `nctl` prerequisites documentation
diff: # Supervisor - cross-platform process manager.
  python3 -m pip install supervisor
  -# Rust toolchain - required by casper-node software.
  +# Rust toolchain and smart contracts - required by casper-node software.
  cd YOUR_WORKING_DIRECTORY/casper-node
  make setup-rs
  +make build-contracts-rs
  ```
  ### Step 2 - extend bashrc file to make NCTL commands available from terminal session.
  