Fix #5179: Add wiki page versions to wiki page secondary links plus standardization

* Call it "Changes" when referring to the global list of changes (pool changes, artist changes, etc).
* Call it "History" when referring to the history of a single item (pool history, artist history, etc).
* Put the artist history search form on the /artist_versions page, and remove the /artist_versions/search endpoint.

config/routes.rb

@@ -67,11 +67,7 @@ Rails.application.routes.draw do
     end
   end
   resources :artist_urls, only: [:index]
-  resources :artist_versions, :only => [:index, :show] do
-    collection do
-      get :search
-    end
-  end
+  resources :artist_versions, only: [:index, :show]
   resources :bans
   resources :bulk_update_requests do
     member do