Planned change to extra attributes of collections

[TomHAnderson]

These are computed fields added to this project early-on

"count": 2,
"total": 2880,
"collectionTotal": 4743

Since then Apigility proper includes these fields

"page_count": 1440,
"page_size": 2,
"total_items": 2880

page_size is the same as count. count will be removed.
total_items is the same as total. total will be removed.
collectionTotal will be renamed to collection_total_items.