Add "login" command documentation
Add "login" command documentation

rnaveiras/vault,hartsock/vault,Aloomaio/vault,Aloomaio/vault,kingland/vault,hartsock/vault,kingland/vault,mgk/vault,kingland/vault,mgk/vault,joelthompson/vault,naunga/vault,hashicorp/vault,joelthompson/vault,joelthompson/vault,quixoten/vault,rnaveiras/vault,mgk/vault,hashicorp/vault,quixoten/vault,Aloomaio/vault,Aloomaio/vault,hartsock/vault,hashicorp/vault,hashicorp/vault,kingland/vault,quixoten/vault,hartsock/vault,hashicorp/vault,rnaveiras/vault,quixoten/vault,hashicorp/vault,mgk/vault,naunga/vault,hartsock/vault,rnaveiras/vault,kingland/vault,rnaveiras/vault,joelthompson/vault