Bug: the deposit metadata is not added to the revision while those are present

According to @olasd's analysis (which i agree with ;), the loader-tar (which is used as the loader-deposit's collaborator) writes its metadata without forwarding the metadata received if any. That's a regression in the loader-tar's behavior (probably introduced in swh-loader-tar!16 (closed)). It must allow client to pass their own metadata and only set its own as a default.

In the mean time, the deposit loaders must be stopped.

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Migrated from T1676 (view on Phabricator)