Reorganization of Orders API documentation

[georgebrindeiro]

Reorganization of Orders API endpoints, including the exclusion of two endpoints:

• [GET] Get feed order status that was used in Feed v2 (which is deprecated)
• [GET] List Order Attachment that was used to fetch attached files from transactional e-mails.

Types of changes

• [ ] New content (endpoints, descriptions or fields from scratch)
• [x] Improvement (make an endpoint's title or description even better)
• [ ] Spelling and grammar accuracy (self-explanatory)