Add field to query organizations for a given user

What does this MR do and why?

Related issue: #417892 (closed)

Add field to query organizations for a given user

This is released as Experimental as Organizations is still experimental

Changelog: changed

Screenshots or screen recordings

How to set up and validate locally

1. Add an OrganizationUser record. In the rails console:

   Organizations::OrganizationUser.create!(organization_id: 1, user_id: 1)

2. Run the following graphql query:

query{
  user(username: "root") {
    organizations {
      nodes {
        path
      }
    }
  }
}

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.