Add `Meta.created` field and search param

[rahul1]

Currently, to figure out when a certain resource was created, users have to use the history Api and search on the client-side. We've had a number of requests for the ability to search on the creation time of a resource (rather than the lastUpdated time) that it would make sense to make this a first-class member of our Meta type, similar to Meta.author

[codyebberson]

I'd like to wait and gather more data points before doing this.

We should treat every custom addition to Meta as a pretty serious change because the blast radius is pretty big.

[ksmith94]

Created PR #3182 , which documents using the history endpoint to find when a resource was initially created.

[healthbjk]

Ah, a classic problem. Some relevant discussion: https://chat.fhir.org/#narrow/stream/179166-implementers/topic/meta.2EcreatedAt

[rahul1]

Since this initial ticket was created, we've had a number of users request this field. The main use case expressed is to have a deterministic sort order for paging through large sets of resources, without having to worry about resources being updated while paging:

• https://github.com/medplum/medplum/issues/4608
• https://medplum.slack.com/archives/C078NUJP6B1/p1720554158566419
• https://medplum.slack.com/archives/C04A55B3VU5/p1710438477973899?thread_ts=1710363533.552519&cid=C04A55B3VU5