Add support for URL as a generator cookbooks parameter to the chef generate commands

[burtlo]

Description

As a user, I want to be able to employ a custom generator cookbook that is specified by URL to produce the various components of my cookbook.

Wouldn't the story that @jjasghar told here be better if he could have written something like the following...

$ chef generate cookbook --generator-cookbook https://github.acme.com/chef/acme-cookbook-generator acme-vim
...
$ cd acme-vim

GitHub

As a user, I want to be able to employ a custom generator cookbook that is specified by GitHub path to produce the various components of my cookbook.

$ chef generate cookbook --generator-cookbook github://acme/acme-cookbook-generator acme-vim
...
$ cd acme-vim 

Supermarket

As a user, I want to be able to employ a custom generator cookbook that is specified by supermarket path to produce the various components of my cookbook.

$ chef generate cookbook --generator-cookbook supermarket://acme-cookbook-generator acme-vim
...
$ cd acme-vim 

[tyler-ball]

Thanks for the well written feature request @burtlo! Getting this moved to the correct repo and triaged appropriately