Add fields for the IPv6 Zone ID

[webmat]

For reasons discussed in elastic/elasticsearch#38064, the ip indexing cannot be adjusted to include support for the Zone ID. Stripping it out is a lossy option, which people are free to do.

But we need to add support for the cases where we want to retain the Zone ID information.

Section 11.3 of RFC 4007 shows a few example of the kind of data that can be expected in a Zone ID. It's mostly likely integers ("1" here: fe80::1234%1), or network device names ("interface10" here ff08::9abc%interface10).

So I suggest we add a sister .ip_zone field everywhere we support an .ip field. This field should be of datatype keyword, and I would have it be an extended field.

[webmat]

@randomuserid Would this solve what you were mentioning yesterday?

[djptek]

Closing as there has been no recent discussion of this topic, please feel free to reopen