Allow filtering out test deposits on the deposit admin page

(I'm not sure why this administration page is in swh.web and not swh.deposit, but here goes)

The https://archive.softwareheritage.org/admin/deposit/ page shows a bunch of test deposits, created by our end to end infrastructure testing.

For now, while the deposit "throughput" is low, these deposits are quite preeminent and clutter the interface.

We should add a toggle to allow filtering them out.

I think this feature request can be adequately turned into adding a "filter by depositing entity" feature.

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Migrated from T2406 (view on Phabricator)