Add support for creating plugins by passing a url to the template

[jtberglund]

This adds support to the CLI for creating plugins from templates passed as

• http/https urls
• git urls
• local directories

This will be helpful for plugin developers as they create their own plugin templates.

Example usage:

buildfire plugin init new-plugin https://github.com/jtberglund/my-custom-plugin

buildfire plugin init new-plugin git@github.com:jtberglund/my-custom-plugin

buildfire plugin init new-plugin ~/dev/my-custom-plugin