Enable read_repository scope for Repositories API

Problem to solve

IIUC, the read_repository PAT is only applicable for the Repository files API. In any case, it does not seem to apply to the Repositories API. This seems a bit strange. In particular it is not possible to get the file archive with a read_repository PAT from a private repo, while it is possible to get all files via the Repository files API one by one.

Intended users

Read-only API users.

Further details

For https://gitlab.com/api/v4/projects/user%2Frepo/repository/archive.tar.gz?ref=master&private_token=my_read_repository_PAT I get {"error":"insufficient_scope","error_description":"The request requires higher privileges than provided by the access token.","scope":"api"}

Proposal

Enable read_repository scope for Repositories API

Permissions and Security

Not known, except that the read_repository scope is extended to the Repositories API

Documentation

Add "Scope" table (first table on page) from Repository files API docs to Repositories API docs

Testing

Unknown

What does success look like, and how can we measure that?

It is possible to download the Repository archive (and possibly blobs?) from a private repo with a `read_repository´ PAT.