Rename the repository

Once the hosts live here the name describes only part of what the repository holds.
Sequenced last deliberately: it gates nothing, and it drags published package coordinates,
release asset URLs and consumer references with it, so there is no reason to spend that
coordination early.

Renaming the repository is not a breaking change for consumers, since the old name
redirects. Renaming a published package is. Those two decisions are separate.

Depends on: #687.

Steps

• Decide the name, and separately whether published package names follow it
• Rename the repository
• Update published package coordinates if that was decided
• Update consumer references and the notify list
• Update the installer and release asset URLs
• Update the documentation site links

Done when

Every published artifact and consumer reference resolves under the new name.