[Iguana] Add to release

Summary:
Build Iguana as part of the release and ship it.

Depends on D16902.

Test Plan: @bot guix-linux guix-win @guix-osx

Reviewers: Fabien, #bitcoin_abc

Reviewed By: Fabien, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D16913