WIP: Replace INET_FAMILY #defines with enums

Please do not merge this PR

This is a WIP for an idea I had and want to see what the rest of you think about it. Currently, for some options, we use a set of #define macros and pass around the values as an int. It would be cleaner to group them correctly as an enumeration and pass it around as such. This also makes the code more readable since it is very obvious what the data type is.

If everyone agrees on this format, I'll spend some more time to migrate the other options as well.