Add skeleton package

Mixture of "meteor create --package" and looking at existing
packages.
More skeleton code

Now only the actual OAuth step is necessary
More Box template code

Shamelessly copied from the equivalent code for Google - although
I'm worried that the code appears to be using a mixture of OAuth1
and OAuth2. I will need to verify what Box actually supports...
Fill in appropriate URLs for Box

And this is pretty much it, OAuth 2.0 is the same everywhere.
That is, barring any required work-around, so testing is needed.

Also, configuration is still missing. I need to understand how
templates really work, because I don't see the input fields
in the Google module.