Feature request: Pre & Post connect execution

[IdefixRC]

What's the feature 🧐

Would be great if we can have an option to add simple pre & post connect commands to the container. This would make updating services based on connection status so much easier (not sure if there is another way currently?). Thanks

Extra information and references

Example how Nordlynx does it:

PRE_UP/POST_UPPRE_DOWN/POST_DOWN Script snippets which will be executed by bash before/after setting up/tearing down the interface, most commonly used to configure custom DNS options or firewall rules. The special string %i is expanded to INTERFACE.