feat: Implement new chunk based upload for standalone artifact bundles

[mitsuhiko]

This implements the necessary changes to permit standalone artifact bundle uploads. The idea is that we check in the chunk upload options to see if we can perform a new style upload and otherwise fall back to release creation and source file upload.

• very old sentry versions did not have global releases, sentry-cli still supports that. This makes some of the existing code read a bit odd
• releases can be created without projects (an antipattern that the UI does not support)
• new style artifact bundles require at least one project to be set, otherwise we fall back to the old logic
• the uploader only supports one project to be passed rather than a list

To do:

• embed an ID directly in the artifact bundle
• add tests

Refs getsentry/sentry#44885

[kamilogorek]

LGTM. I don't like few parts, but we've got to work with what we have :P