Added CKAN support.

You can place this file anywhere in the distro, and with any
name, as long as it has a `.ckan` extension.

The only time you'll need to update it is if you're changing
how the mod is installed, if you're targetting a new version
of KSP, or any of the other data that's hard-coded into this
file (homepage, author, license, etc).

You *do not* need to update this file if you're just making a
new release. Our bot does all the hard work there.

If the CRP supports any version of KSP above a certain release,
you can replace `ksp_version` with `ksp_version_min`.

If the CRP supports any version of KSP at all, you can use
`"ksp_version" : "any"`.

The CRP will probably be up on the CKAN tonight, but any new
mod releases will use the metadata contained in this file.

Many thanks again!

~ Paul