Combine uuid-old and uuid branch changes

- Switch to binary 16 for UUID keys
- Remove AccountScopedRecord base class, all model use binary uuids now
- Fix the search sql to serialize uuids properly
- Patch the MySQL schema dumper to output binary lengths

app/models/application_record.rb

@@ -1,5 +1,7 @@
 class ApplicationRecord < ActiveRecord::Base
   primary_abstract_class
 
+  attribute :id, :uuid, default: -> { ActiveRecord::Type::Uuid.generate }
+
   connects_to database: { writing: :primary, reading: :replica }
 end