CONTRIBUTING: provide a template for new issues

_maybe_ we could even automate this to populate and complain in some
situations.

I see https://github.com/isaacs/github/issues/99 that is old and needs
some love from @github ...

@tianon @unclejack @shykes 

Signed-off-by: Vincent Batts <vbatts@redhat.com>
Why not just do something simple like `docker version` and if that fails, try `sudo docker version` ?  Or better yet, check if they're in the `docker` group, but that's configurable...  Who made that configurable anyhow? :smile: