Empty folders in backup and restore, a full disk stops a restore, progress in the Bin

- Record folders without files in the meta record of a snapshot and restore them (#27)
- Errors writing to the restore directory stop the restore, also with --salvage
- Resume: check the folder before skipping, clean temporaries in folders that are complete
- Clean only read-ahead folders of our own; refresh the lease on skipped files
- Drop tables a failed database restore created; keep --salvage from calling a restored database fresh
- Retry a pack that fails to open on the storage (SMB)
- Without cron, running backups take turns from the open page
- Bin: read in parts with a counter and progress bar, show read errors, refresh when a run ends

src/api.js

@@ -21,7 +21,7 @@ export default {
 	addSlot: (passphrase, label) => call('post', '/key/slots', { passphrase, label }),
 	replaceSlot: (slot, passphrase, label) => call('put', `/key/slots/${slot}`, { passphrase, label }),
 	removeSlot: (slot) => call('delete', `/key/slots/${slot}`),
-	trash: (targetId) => call('get', `/targets/${targetId}/trash`),
+	trash: (targetId, offset = 0) => call('get', `/targets/${targetId}/trash`, { offset }),
 	untrash: (targetId, snapshotId) => call('post', `/targets/${targetId}/trash/${snapshotId}`),
 	kitUrl: () => url('/key/kit'),
 	confirmKit: (accepted, phrase, code) => call('post', '/key/confirm', { accepted, phrase, code }),