posts: remove rating, note, and status locks.

Remove the ability for users to lock ratings, note, and post statuses.

Historically the majority of locked posts were from 10+ years ago when
certain users habitually locked ratings and notes on every post they
touched for no reason. Nowadays most posts have been unlocked. Only a
handful of locked posts are left, none of which deserve to be locked.

The is_rating_locked, is_note_locked, and is_status_locked columns still
exist in the database, but aren't used.

app/logical/post_query_builder.rb

@@ -162,8 +162,6 @@ class PostQueryBuilder
       child_matches(value)
     when "rating"
       Post.where(rating: value.first.downcase)
-    when "locked"
-      locked_matches(value)
     when "embedded"
       embedded_matches(value)
     when "source"
@@ -470,19 +468,6 @@ class PostQueryBuilder
     end
   end
 
-  def locked_matches(query)
-    case query.downcase
-    when "rating"
-      Post.where(is_rating_locked: true)
-    when "note", "notes"
-      Post.where(is_note_locked: true)
-    when "status"
-      Post.where(is_status_locked: true)
-    else
-      Post.none
-    end
-  end
-
   def table_for_metatag(metatag)
     if metatag.in?(COUNT_METATAGS)
       metatag[/(?<table>[a-z]+)_count\z/i, :table]