Allow passing the IP address where the router console is reachable when running a Docker container
My solution to: https://i2pgit.org/i2p-hackers/i2p.i2p/-/merge_requests/67 credit to 31337 for the original MR, but I needed to follow up on the patch itself. It adds the ability to pass an IP_ADDR environment variable to the docker run command to control the IP address where the router console is reachable. It also expands the grep to discover non-default docker networks when running without an IP_ADDR environment variable.