Bump up priority on Transactions

[TheCaffinatedDeveloper]

Recently found this library to use in our testing pipeline. Seems to have great FHIR standard coverage and is precisely what we needed for lightweight testing.

My ask is that Transaction support gets more ❤️ 🙏 . When using a FHIR store as more than just a HIE (like powering EHR-like functionality) you often need to leverage creating multiple resources that reference each other simultaneously. Given the complexity in functionality - this is what would need to be tested more heavily.

The implementation isn't trivial but hopefully it can get into the High-Priority section 🤞

Thanks again