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/logical/meta_searches/tag.rb

@@ -1,30 +0,0 @@
-class MetaSearches::Tag
-  MAX_RESULTS = 25
-  attr_reader :search_params, :tags, :tag_aliases, :tag_implications
-
-  def initialize(search_params)
-    @search_params = search_params
-  end
-
-  def load_all
-    load_tags
-    load_tag_aliases
-    load_tag_implications
-  end
-
-  def load_tags
-    @tags = ::Tag.name_matches(name_param).limit(MAX_RESULTS)
-  end
-
-  def load_tag_aliases
-    @tag_aliases = TagAlias.name_matches(name_param).limit(MAX_RESULTS)
-  end
-
-  def load_tag_implications
-    @tag_implications = TagImplication.name_matches(name_param).limit(MAX_RESULTS)
-  end
-
-  def name_param
-    search_params[:name] || ""
-  end
-end