Add knife-config gem and knife-aliases.sh to profile

I recommend setting chef_server_url in your knife.rb
with an environment variable CHEF_URL.  That makes
it easier to point knife and other tools
(e.g. Berkshelf) to a specific URL such as one
for a chef-zero server.

The knife-config gem and kgu/ksu aliases make it easy
to get/set the chef_server_url configuration.