* Add NS1 DNS provider.
Integrates Lego with NS1 using their rest API.
It uses NS1's official Go package as client:
https://github.com/ns1/ns1-go
Signed-off-by: David Calavera <david.calavera@gmail.com>
* Add NS1 to the cli handlers.
Signed-off-by: David Calavera <david.calavera@gmail.com>
