Better pagination support

[James-Mart]

Plugins may want to expose paginated graphql queries to front-ends.

For this, we probably want a PageInfo object exposed by the host that the plugin can attach to a graphql request, and the host knows how to modify the request to add pagination details. The plugin can then expose the PageInfo object in its functions to offer the UI pagination support.

Also, the query service will expose a graphql pagination schema, but under the hood if we are querying events it has to convert the pageinfo into an sql query. Confirm that the sqlite database can support everything expected re: pagination for a graphql user.