Geo - Support Parameterized Registries via GraphQL

What/Why

Related to #216969 (closed)
Follow up from !32872 (closed)

Currently, when querying GraphQL for Geo Registry endpoint, you must know the registry's name. Ex: packageFileRegistries

query($before: String!, $after: String!) {
  geoNode {
    packageFileRegistries(first: 20, before: $before, after: $after) {
      edges {
        ...
      }
    }
  }
}

However, with the need to be Generic for the frontend, we need a way to pass a variable to the query based on which registry we want.

Example of what I believe is NOT possible:

query($registry: String!, $before: String!, $after: String!) {
  geoNode {
    $registry(first: 20, before: $before, after: $after) {
      edges {
        ...
      }
    }
  }
}

Proposal

Refactor the Geo GraphQL endpoint a bit to support a parameterized lookup of registries, for example:

query($registry: String!, $before: String!, $after: String!) {
  geoNode {
    geoRegistry(registry: $registry, first: 20, before: $before, after: $after) {
      edges {
        ...
      }
    }
  }
}

This will allow us to continue to key off a single registry key for routes, views, and GraphQL

cc: @mkozono