For issue #56: add deprecation warning to deprecated launch files

As discussed in #56, this results in a warning message being printed to the console whenever these launch files are used.

I propose to also delete the joint limited launchfiles from the root of the package: I copied them to the `launch` subdirectory where I think they should be (ie: new files, not deprecated and part of the default set of files). I can add a commit removing those in the root if desired.