users_prune needs to paginate through results

[DaedalusG]

#901 (comment)
See the above comment for more details

Currently the following query returns only returns the first 100 users:

query InactiveUsersShort {
  site {
    users {
      nodes {
        id
        username
        email
        siteAdmin
        lastActiveAt
      }
    }
  }
}

Results need to be paginated