Use docker login credentials from host

I had a lot of failures for pulling the docker images lately,
so I was looking for a way to connect using docker login.
This PR sends the docker login credentials from the host to
the swarm server.

cli/app/deploy.go

@@ -151,11 +151,12 @@ checkout as-is. Recipe commit hashes are also supported as values for
 
 		stackName := app.StackName()
 		deployOpts := stack.Deploy{
-			Composefiles: composeFiles,
-			Namespace:    stackName,
-			Prune:        false,
-			ResolveImage: stack.ResolveImageAlways,
-			Detach:       false,
+			Composefiles:     composeFiles,
+			Namespace:        stackName,
+			Prune:            false,
+			ResolveImage:     stack.ResolveImageAlways,
+			Detach:           false,
+			SendRegistryAuth: true,
 		}
 		compose, err := appPkg.GetAppComposeConfig(app.Name, deployOpts, app.Env)
 		if err != nil {

cli/app/rollback.go

@@ -166,11 +166,12 @@ beforehand. See "abra app backup" for more.`),
 
 		stackName := app.StackName()
 		deployOpts := stack.Deploy{
-			Composefiles: composeFiles,
-			Namespace:    stackName,
-			Prune:        false,
-			ResolveImage: stack.ResolveImageAlways,
-			Detach:       false,
+			Composefiles:     composeFiles,
+			Namespace:        stackName,
+			Prune:            false,
+			ResolveImage:     stack.ResolveImageAlways,
+			Detach:           false,
+			SendRegistryAuth: true,
 		}
 
 		compose, err := appPkg.GetAppComposeConfig(app.Name, deployOpts, app.Env)

cli/app/upgrade.go

@@ -178,11 +178,12 @@ beforehand. See "abra app backup" for more.`),
 
 		stackName := app.StackName()
 		deployOpts := stack.Deploy{
-			Composefiles: composeFiles,
-			Namespace:    stackName,
-			Prune:        false,
-			ResolveImage: stack.ResolveImageAlways,
-			Detach:       false,
+			Composefiles:     composeFiles,
+			Namespace:        stackName,
+			Prune:            false,
+			ResolveImage:     stack.ResolveImageAlways,
+			Detach:           false,
+			SendRegistryAuth: true,
 		}
 
 		compose, err := appPkg.GetAppComposeConfig(app.Name, deployOpts, app.Env)