`denote-explore-identify-duplicate-notes` could instead use `find-dired`

[swflint]

I think it might be interesting to extend the UI for denote-explore-identify-duplicate-notes to use find-dired, which provides a number of features that could make it easier to fix issues with duplicate IDs (e.g., using wdired or dired+ related filtering features).

I'll PR in a bit.

[pprevos]

I like your thinking. I had planned to look into something similar.