Copy in boilerplate .rubocop configuration

If there is no local .rubocop.yaml we may as well copy in the one from the boilerplate.

The rubocop job runs:

cd code
bundle exec rake rubobcop

and uses the file .rubocop.yaml in the code directory.

Up to now we have expected the user to copy the boilerplate files into the working code directory and commit them. Doing this cp is one less item for the user to do and will make more of the rubocop tests more useful. We make the copy conditional on there not being a file present for the case where the rubocop.yml is maintained upstream or has been modified. Note we never modulesync files in the code directory by design to avoid stomping on upstream.