Remove /meta_searches/tags page.

This was a search page that let you search for tags, aliases, and
implications at the same time. It never got much use and it's been
broken for a while now (the search form passed the wrong param to the
controller).

app/controllers/meta_searches_controller.rb

@@ -1,6 +0,0 @@
-class MetaSearchesController < ApplicationController
-  def tags
-    @meta_search = MetaSearches::Tag.new(params)
-    @meta_search.load_all
-  end
-end