Go IPv6 utilities

After spending some time with Python, I moved to Go, which seems to suit the way my brain works slightly better (make no mistake, I am still a poor developer). Keeping in line with the work done on this, I endeavored to re-write this in Golang, mostly because the subnet generation in python had some resource issues with large blocks. And off I went. With the help of an LLM to get me past weird errors and inability to compile, the resulting code is surprisingly efficient and useful - available here