32818 add attachments

- Added attachment handling to CDTMutableDocumentRevision via the attachments property
- Depercated old attachment API in CDTDatastore+attachments.h
- Created new Attachment CRUD tests based off AttachmentCRUD.m
Change the attribution and date; and add the standard Apache licence header. I guess you copied this from AttachmentCrud.m which doesn't have the licence header either.