cli: Fix 'api network route' output

Fixes #535

* Changed op type for 'GET /network/routes' from 'array' to 'Routes'
* Added renderer for 'Routes'

Signed-off-by: Nehal J Wani <nehaljw.kkd1@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>