Unified hacking tools for FHIR packages (do it on canonicalManager side)

[ryukzak]

Check the possibility to remove patchSd from the registry and replace it with the canonical manager preprocessPackage.

Motivation:

• Have only one place for such tricks;
• Hide the registry from the codegen user.

Examples to be merged:

• https://github.com/atomic-ehr/codegen/blob/main/examples/nodge-r4.ts
• https://github.com/atomic-ehr/codegen/blob/main/examples/typescript-ccda/generate.ts