[chef] Deprecating the rake tasks

[Bryan McLellan < >]

The rake tasks such as 'rake new_cookbook' are from the time that we
used rake to manage the cookbook hierarchy on the Chef server because
we did not yet have an API for uploading cookbooks to the server.
Knife has now replaced the chef-repo rake tasks and we're deprecating
them. [1]

If there are any rake tasks that don't have equivalents in knife,
please check to see if there is a ticket for adding this feature, and
if not, create one.

Thanks!

Bryan

[1] http://tickets.opscode.com/browse/CHEF-2353