Harmonize commands flavor

ATM we have
```
$> dandi --help | sed -ne '/Commands:/,9999p'
Commands:
delete Delete dandisets and assets from the server.
digest Calculate file digests
download Download a file or entire folder from DANDI.
instances List known Dandi Archive instances that the CLI can...
ls List .nwb files and dandisets metadata.
organize (Re)organize files according to the metadata.
shell-completion Emit shell script for enabling command completion.
upload Upload Dandiset files to DANDI Archive.
validate Validate files for NWB and DANDI compliance.
validate-bids Validate BIDS paths.
```

A new `git mv` inspired by `git mv` is being suggested (TODO). But we have `delete` not `rm`. We do have `ls` and not `list`.

So we have mixing of concise abbreviated (`ls` and `mv`) and verbose (`delete` not `rm`, `download` not some `get`). For consistency may be we should get to one flavor. As much as like concise, I think we better go with verbose and rename `ls` into `list` and any new command should also stay verbose. WDYT @dandi/dandi-cli -- allow for some concise (`rm`, `mv`, `ls`) or make them all verbose (`delete`, `move`, `list`)?