/engine endpoint should accept uploads to any container level

[gsfr]

We currently only accept uploads to acquisitions.

We desire the following functionality:

• Uploads to an acquisition, its parent session and parent project
• Uploads to a session and its parent project
• Uploads to a project (not sure this is actually a thing)

[kofalt]

Blocked by #159

[nagem]

As of #357, you are able to upload to an analysis, acquisition, session, or project. Uploading to multiple levels of the hierarchy at the same time, if still necessary, can be done in a separate PR.

[kofalt]

SGTM. We don't have anything on the roadmap regarding gears simultaneously uploading to multiple levels of the hierarchy.

[gsfr]

We should have our schemas enforce this limitation.