feat: add support for custom device hostname (#789)

Configure via --hostname (or -n) flag in the `up` and `login` commands
---------

Signed-off-by: Chinmay D. Pai <chinmay.pai@zerodha.com>

client/cmd/login.go

@@ -15,6 +15,7 @@ import (
 
 	"github.com/netbirdio/netbird/client/internal"
 	"github.com/netbirdio/netbird/client/proto"
+	"github.com/netbirdio/netbird/client/system"
 )
 
 var loginCmd = &cobra.Command{
@@ -32,6 +33,11 @@ var loginCmd = &cobra.Command{
 
 		ctx := internal.CtxInitState(context.Background())
 
+		if hostName != "" {
+			// nolint
+			ctx = context.WithValue(ctx, system.DeviceNameCtxKey, hostName)
+		}
+
 		// workaround to run without service
 		if logFile == "console" {
 			err = handleRebrand(cmd)