* Move snap un-dumpers to aristo unit test folder
why:
The only place where it is used, now to test the database against
legacy snap sync dump samples.
While the details of the dumped data have mostly outlived their purpuse,
its use as **entropy** data thrown against `Aristo` has still been
useful to find/debug tricky DB problems.
* Remove cruft
* `nimbus-eth1-blobs` not used anymore as test data source
Jordan Hrycaj