Use GraphQL to efficiently request details of multiple repositories (enhancement)

[jamestelfer]

Proposed enhancement to use the GH GraphQL API to retrieve repository details in batches, instead of one by one via REST. This would be useful for the list supplied to --repo, as well as the code search functionality introduced in #399.

Coming from a suggestion in #399:

Nice to have (no need if you don't want to) would be to use the v4 (GraphQL) API to fetch all of these with one request.
That is true for --repo as well, but maybe even more here since I guess it will normally be more returns.

On further investigation, I was uncertain whether the GraphQL API would supply all the required information:

I'm not sure that there's a direct equivalent of the permissions element returned by REST. There's a similar field (viewerPermission), but it has some caveats.

The users permission level on the repository. Will return null if authenticated as an GitHub App.

[jamestelfer]

Prototyping query

{
  repository(owner: "lindell", name: "multi-gitter") {
    name
    nameWithOwner
    owner {
      login
    }
    defaultBranchRef {
      name
    }
    createdAt
    isArchived
    isDisabled
    isFork
    sshUrl
    url
    viewerPermission
    repositoryTopics(last: 50) {
      nodes {
        topic {
          name
        }
      }
    }
  }
}