[Chore] Merge `ithaca` branch in `master`

Description

Ithaca has been successfully activated, so we can now merge the dedicated branch in master.

Note: there is still one ithaca-related issue left open at the time of writing: #789 (closed) . This issue however, as other that may appear in the future, is not strictly required to support the ithaca protocol.

Related issue(s)

Note: gitlab doesn't close issues if the MR is not targeting master, so:

Resolves #764 (closed)

Resolves #765 (closed)

✅ Checklist for your Merge Request

Related changes (conditional)

• Tests (see short guidelines)

  • If I added new functionality, I added tests covering it.
  • If I fixed a bug, I added a regression test to prevent the bug from silently reappearing again.

• Documentation

  • I checked whether I should update the docs and did so if necessary:
    • Root README and other README.md files
    • Haddock
    • docs/
  • I updated changelog files of all affected packages released to Hackage if my changes are externally visible.

Stylistic guide (mandatory)

• My commits comply with the following policy.
• My code complies with the style guide.