Auction paginator v2

This MR change returned data from /api/auctions endpoint

Before:

[auction_obj, auction_obj, auction_obj]

Now:

{
  'auctions': [auction_obj, auction_obj, auction_obj],
  'paginator': {
    'curr_page': 1,
    'prev_page': None,
    'next_page': 2,
    'last_page': 3,
    'limit': 10
  }
}