feat: app services command

Closes coop-cloud/organising#372

pkg/config/app.go

@@ -45,9 +45,9 @@ type App struct {
 	Path   string
 }
 
-// StackName gets what the docker safe stack name is for the app. This should
-// not not shown to the user, use a.Name for that. Give the output of this
-// command to Docker only.
+// StackName gets whatever the docker safe (uses the right delimiting
+// character, e.g. "_") stack name is for the app. In general, you don't want
+// to use this to show anything to end-users, you want use a.Name instead.
 func (a App) StackName() string {
 	if _, exists := a.Env["STACK_NAME"]; exists {
 		return a.Env["STACK_NAME"]