Add support for ip_range range datatype

[arledesma]

It looks like an implementation of the ip_range range datatype that was introduced in 5.5 is needed.

• https://www.elastic.co/guide/en/elasticsearch/reference/5.5/range.html
• https://www.elastic.co/guide/en/elasticsearch/reference/5.5/release-notes-5.5.0.html#feature-5.5.0
• Add new ip_range field type elasticsearch#24433

[russcam]

Thanks for opening @arledesma, we'll look to get these in the next 5.x and 6.x releases 👍