Rename admin users controller/route

Started out as a simple helper page to list LDAP users, but turning into
proper user management now.

app/controllers/admin/users_controller.rb

@@ -0,0 +1,20 @@
+class Admin::UsersController < Admin::BaseController
+  before_action :set_current_section
+
+  def index
+    ldap = LdapService.new
+    @ou = params[:ou] || "kosmos.org"
+    @orgs = ldap.fetch_organizations
+    @entries = ldap.fetch_users(ou: @ou)
+    @stats = {
+      users_confirmed: User.where(ou: @ou).confirmed.count,
+      users_pending: User.where(ou: @ou).pending.count
+    }
+  end
+
+  private
+
+  def set_current_section
+    @current_section = :users
+  end
+end