OrganizationRepoLists class

The repositories the registered organizations currently offer, asked for once per organization and run.

Whether an organization owns a repository is decided by the list the platform reports — the same list gg do upgrade ocean syncs the ocean against — and not by whether its url answers. A url keeps answering long after the repository is gone: GitHub redirects a renamed or transferred repository from its former name, so git ls-remote on the old organization still succeeds. Deciding by that url is what made gg do add <name> offer a repository under an organization the sync had just moved it out of.

One gg do add may ask about many names — every missing transitive dependency is looked up the same way — so the lists are memoized: each organization is asked once, however many names are checked against it.