support skipping count aggregate on hasura

[mohammad-bolt]

issue: #117

current hasura graphql provider always make an aggregate count call

tota: table(
    order_by: $order_by
    where: $where
  ) {
    aggregate {
      count
      __typename
    }

which is very expensive on most RDMS like postgres.

this PR introduces a very simple workaround. when caller providers
aggregateFieldName(resource) = NO_COUNT we simply skip count call and provide partial pagination instead.

This is a NO-OP unless caller provide custom aggregateFiledName function.

TEST

called sample app with and without

aggregateFieldName: (_) => "NO_COUNT"

and verified the behavior.

[arjunyel]

@mohammad-bolt thank you so much! When you have a moment could please you add this to the readme?