Add Piwigo in Photo Storage

[jonidimo]

I suggest including Piwigo in the Photo Storage list, as it is not currently listed and offers the advantages of being open-source software. In my opinion, Piwigo is even more trustworthy than Photoprism, which has been reported to disable certain functionalities and make them paid features without informing users beforehand. Despite their claim of prior announcements, similar to what occurred with the maps, Piwigo presents itself as a more reliable option.