Add option to stop/start stack

Since the V2 of Portainer API it is possible to "restart" a stack. It would be nice to add this option

Useful documentation:

https://app.swaggerhub.com/apis/deviantony/Portainer/2.0.1#/stacks/StackStop https://app.swaggerhub.com/apis/deviantony/Portainer/2.0.1#/stacks/StackStart