Add option to automatically load transitive dependencies

[mint-thompson]

Transferred from internal JIRA issue originally created 2024-06-24.

Technically, SUSHI should load transitive dependencies so that all references from a dependency are complete. As it is now, users have to manually add necessary transitive dependencies to their dependency list. This is not ideal.

See: https://chat.fhir.org/#narrow/stream/215610-shorthand/topic/dependency.20resolving.20recursive/near/406283949

Note that at the time of opening this issue, there is a large refactor in process for FPL. This task should not be started until that refactor is completed.

[cmoesel]

As part of this implementation, FPL will need to properly support version resolution as best it can when a resource is referenced without a version. See this discussion on Zulip.