Add support for --detach/-d flag in stack rm

Added --detach/-d to stack rm. Setting --detach=false waits until
all of the stack tasks have reached a terminal state.

Co-authored-by: Sebastiaan van Stijn <github@gone.nl>
Signed-off-by: George Margaritis <gmargaritis@protonmail.com>

cli/command/stack/options/opts.go

@@ -38,6 +38,7 @@ type PS struct {
 // Remove holds docker stack remove options
 type Remove struct {
 	Namespaces []string
+	Detach     bool
 }
 
 // Services holds docker stack services options