dedup --strategy

[BoPeng]

Is your feature request related to a problem? Please describe.
Right now, the dedup command has a built in strategy, namely keeping the file with the longest path. The logic is that the longer path represent some "annotations", namely additional suffix to filename (e.g. xxxxxxxx-xxxxxx-Henry.jpg for photos from Henry's phone, or /path/to/2020-04-Vacation/xxxxxxxx-xxxxxxxx.jpg for keeping photos in a specific album. However, some other strategies could be supported.

Describe the solution you'd like
An option --strategy for, for example, keeping files in specific folders. For example, a way to remove all the _1 and _2 files when the same files are stored to the directory multiple times could be helpful.