Deduplication #220

Really enjoying the app - it is (almost) perfect for my usecase.
One quick question. I get quite a lot duplicates scanning immoscout and eg. immonet.
I dont know how the deduplication is implemented but maybe there could be an (optional) additional check for the title image (first image of the listing) - maybe matching against price just to be sure. This should cover a lot more duplicates.

only problem i see are listings for new houses, which often have the same first advertising image. but i dont want them anyway -> optional toggle?

Thanks in advance!