Allow templating in apm's init

[rgbkrk]

This probably belongs in apm, but since that repo isn't available this seems like the next best entrypoint.

package-generator is using apm init underneath to generate packages. It would be great if the package defaulted to setting the

• repository name in package.json to https://github.com/{{ username|configured_org }}/{{ package_name }}
• full name in LICENSE.md
• license the user prefers

The first two I'm sure are linked to their configured GitHub account anyway, so those can probably be slurped directly with no user interaction. The third requires user input "somewhere", possibly on the settings pane for this package.

There are more steps I'd like to automate to make sure people are using the right flow, but this at least saves people from having to do boilerplate work.