upload,validate: Add --validators option

ATM we already interface multiple validators in dandi-cli. There are use cases which might ask for disabling or enabling some. Eg.

- in cases of partial [uploads of BIDS datasets](https://github.com/dandi/dandi-cli/issues/1734#issuecomment-3498630860) we might want to disable bids-validator-deno as it would not have access to full dataset and just rely on bidsschematools which I believe we do not report otherwise (we do use it to extract metadata though)
- ...

So I think we should add an option like

- `--validators auto,all,bidsschematools,bids-validator-deno,zarr,...`

where currently it is like `auto` as we do not bother with bids-validator(s) if we do not see it being a bids dandiset. With `all` it would really enable all of them.

Also I now created `configuration` label to mark issues which would point to specific options people must be able to specify for their dandisets locally (or globally).

edits:
- note that such filtering on validators, relates to the #1743
- it is not to "force" any particular validator on a specific path, but rather to alter (shrink) list of available validators which are applied as applicable.
- for now `blocked` as we better decide on how to address is more holistically with 1743 and others.