Change IP lookup webservice to one that preferably returns IPv4 over …

[hypnotortoise]

…IPv6, when both are available.

This is required as ursulas cli option for "rest-host" expects an IPv4 (see https://github.com/nucypher/nucypher/blob/736f8f9cbbe1eb06bb071b9d8eec6eacfc2e79a6/nucypher/utilities/networking.py#L42-L48)

Type of PR:

• Bugfix
• Feature
• Documentation
• Other

Required reviews:

• 1
• 2
• 3

What this does:

High-level idea of the changes introduced in this PR.
List relevant API changes (if any), as well as related PRs and issues.

Changes the URI request URL to something accessible for hosts that contain both IPv6/IPv4 global interfaces, to return the IPv4 variant.

Issues fixed/closed:
None

Why it's needed:

Explain how this PR fits in the greater context of the NuCypher Network.
E.g., if this PR address a nucypher/productdev issue, let reviewers know!

As long as TACo node does not accept IPv6 binding address for rest-host, this is a requirement for hosts that contain both IPv6/IPv4 global interfaces.

Notes for reviewers:

What should reviewers focus on?
Is there a particular commit/function/section of your PR that requires more attention from reviewers?

No. Only replacement of ip lookup webservice that is queried for IPv4 public address.