Make the WebHook URL changeable

[thomaspkd]

Is your feature request related to a problem? Please describe

we use portainer-ee lts version.
We use webhook URL in Portainer Stacks. Our pipeline triggers the url on special conditions to tell portainer to update the stack. Sometimes we have to recreate the stack (delete and deploy again). Then we want to have the same webhook-url then the previous stack. Otherwise, we have to change our trigger-code to the new generated webhook urls.

Describe the solution you'd like

Please make the webhook URL from an portainer stack writeable/changeable.

Describe alternatives you've considered

we couldn't use the git polling mechnism of portainer, because only "changes in repository" are not our only characteristic, when a Stack should redeploy.

Additional context

No response