models: remove creator_id from artists, notes, and pools.

Remove the creator_id field from artists, notes, and pools. The
creator_id wasn't otherwise used and was inconsistent with the
artist/note/pool history in some cases, especially for old artists.

app/views/notes/index.html.erb

@@ -19,8 +19,6 @@
         <% end %>
       <% end %>
       <% t.column "Created" do |note| %>
-        <%= link_to_user note.creator %>
-        <%= link_to "»", notes_path(search: { creator_name: note.creator.name }) %>
         <div><%= time_ago_in_words_tagged(note.created_at) %></div>
       <% end %>
     <% end %>

app/views/notes/search.html.erb

@@ -6,7 +6,6 @@
       <%= f.hidden_field :group_by, value: "note" %>
 
       <%= f.input :body_matches, label: "Body" %>
-      <%= f.input :creator_name, label: "Author", input_html: { data: { autocomplete: "user" } } %>
       <%= f.input :post_tags_match, label: "Tags", input_html: { data: { autocomplete: "tag-query" } } %>
       <%= f.submit "Search" %>
     <% end %>