Add a rake task to pulling role/env/node definitions in json files

I keep all my role and environment definitions in json so that when people edit them through the webui, I can still pull it back into version control. Would be nice if there was a rake task for this, then we could just pull each role/env/node one-by-one and write to file with --format=json – the person performing the task could view the diff and merge if it makes sense.

Anyhow, just a thought