Refactor HAL code from ::ItemWritable to new ::ItemWritableHAL
Use builder for content_types_accepted in ItemWritable*
Add/bump some prerequisite module versions
Refactor Item to move HAL code into new ItemHAL role.
Refactor Set to move HAL code into new SetHAL role.
Refactor HAL code from ::SetWritable to new ::SetWritableHAL role
Refactor ::SetRender out of existence
Change error response type from hal+json to json. Add note re vnd.error
Refactor render_item_as_hal_hash out of DBIC into new DBIC_HAL role
Group HAL support in the Generic* roles