Closes #3799: Remove NaturalOrderingManager

[jeremystretch]

Fixes: #3799

• Introduce NaturalOrderingField for storing pre-rendered natural ordering-friendly values on models
• Introduce naturalize() and naturalize_interface() to handle generating values suitable for natural ordering
• Add a NaturalOrderingField (_name) to the site, rack, and device models, as well as all device components and component templates
• Extend schema migrations to automatically generate naturalized values for existing objects
• Remove NaturalOrderingManager
• Remove custom ordering logic from InterfaceManager