FEATURE REQUEST: Allow apps to have their own IP in Electric Eel

Here’s an alternative to this request, which I think is more practical for inclusion in EE, even post release.

The difference is this is not providing a dedicated IP to a container/app, but rather allowing an app to to bind a port to a specific IP, which is created as an IP alias on a network interface.

I have already tested and this does work quite well in compose, and I believe should be able to be implemented in the current app system (ie with the existing questions/templates etc)

It just needs to be done for the apps.