mod dashboard: remove ip address search.

Remove the IP address search option from the /moderator/dashboard page.
This was an obsolete way of searching for sockpuppet accounts by IP.
The /user_events page should be used instead.

app/controllers/moderator/ip_addrs_controller.rb

@@ -1,17 +0,0 @@
-# frozen_string_literal: true
-
-module Moderator
-  class IpAddrsController < ApplicationController
-    respond_to :html, :json
-
-    def index
-      authorize IpAddress
-      @search = IpAddrSearch.new(params[:search])
-      @results = @search.execute
-      respond_with(@results)
-    end
-
-    def search
-    end
-  end
-end