Use an actual cursor for relay style pagination

While the implementation for Relay/Connection pagination is compliant with the Relay spec, it does not actually implement cursor based pagination but rather offset-based pagination in disguise. Read about the difference here https://www.sitepoint.com/paginating-real-time-data-cursor-based-pagination/

This is a hard problem to solve, since there is no easy way to reliable get the next page after a cursor, unless we are basing the sort order on an ordered index.

https://stackoverflow.com/questions/26188519/handling-paging-with-changing-sort-orders

Since i do not think we can find a generalized solution that fits all use cases, we might
limit the scope of Lighthouse to providing just a basic API for the user to implement their own, cursor-based pagination resolver. We can take care of providing helpers for encoding/decoding the cursor, but apart from that, the use cases can be so vastly different we can not possibly cover them all.

Maybe something like https://github.com/lampager/lampager-laravel might provide us with a nice framework to build cursor pagination.

No files, tests, or entry points are named. Start by locating Lighthouse's Relay/Connection pagination implementation and review the linked cursor-pagination references. Define the scope for a basic user-provided cursor pagination resolver and cursor encoding/decoding helpers; done should reflect an agreed API rather than a generalized pagination solution.