Align metadata uploader script with standard async setup

[anfimovdm]

Summary

scripts/upload_repository_metadata.py was still on the legacy async entrypoint: syncer.sync(main()) plus a hand-assembled open_async_session(get_async_db_key()), and it never called setup_all(). This aligns it with the pattern every other script in scripts/ uses (see scripts/noarch_checker.py).

Note that the missing setup_all() looks like a latent bug rather than a cosmetic gap — MetadataUploader needs both the async session key and the sync 'pulp' key (alws/utils/uploader.py calls open_session('pulp')), and fastapi_sqla_setup.setup_all() is what registers those session factories.

Changes

• scripts/upload_repository_metadata.py
  • sync(main()) -> asyncio.run(main()), dropping the syncer dependency
  • added await setup_all() at the top of main(), after arg validation so the early return 1 path doesn't pay DB setup cost
  • open_async_session(get_async_db_key()) -> the get_async_db_session() context manager from alws.dependencies (an @asynccontextmanager wrapping the exact same call, so commit/rollback semantics are unchanged)
  • removed the now-unused syncer, open_async_session, get_async_db_key and asynccontextmanager imports

Testing

• python -m py_compile passes; sys.exit(...) still propagates the return 1 exit code from the no-file-specified path
• Verified the new imports resolve: get_async_db_session at alws/dependencies.py:26, setup_all at alws/utils/fastapi_sqla_setup.py:16
• Diffed against the ~25 sibling scripts already on this pattern to confirm ordering (setup_all() before any session is opened)
• No automated test covers this script; not run against a live DB/Pulp instance.