Convert all ACF reference fields to reference ID

[rpeterman-gp]

ACF reference fields are always expanded and do not contain all needed data (ie. ACF fields on the reference), so additional requests would be needed. To lighten the payloads for ACF data, convert them to only return the reference ID.

[brandonhundt]

@rpeterman-gp I feel like you completed this one, yea? Close if true.

[rpeterman-gp]

This was partially done, but is irrelevant with the GraphQL API. Closing.