Restore BIDS metadata integration for `dandi ls`

[jwodder]

See #1076 (comment) for more information.

[TheChymera]

@jwodder are you satisfied with this? 44a8ab4

[jwodder]

@TheChymera If the tests pass, then I'm satisfied.

[TheChymera]

@jwodder how did you link the PR to close this issue? I thought the Closes: ... lines in the commit text body already do that — but those don't show up 🤔

[jwodder]

@TheChymera I added "Closes #1097" to the text of the top comment in the PR. I think text in commit messages has to be on the first line in order for GitHub to recognize it.