I'm looking for places or repositories where is the information collected by the Cassini mission including the Huygens probe at Titan, ideally curated or organized in some way.
For a start read the Wikipedia article. The next step would be the more than 100 references at the bottom. Many links to NASA, JPL and ESA documents.
The Cassini-Huygens mission was a fantastically successful flagship-class mission to the Saturn system, with the Cassini spacecraft spending 13 years in orbit there and delivering the Huygens probe that made the first successful hard-surface landing in the outer solar system. The results are so voluminous, and cover so many different aspects of the Saturn system and so many scientific disciplines, that even a brief overview of the most intriguing results would be far more than any popular press article could accept.
There are online sites hosted by NASA and ESA with information about Cassini and Huygens, but I found the NASA highest-level Cassini site lacking, with no useful links to pages with more detailed information. The ESA site is better in this respect than the NASA site, even for Cassini, and contains those links the NASA site lacks — to NASA pages!
For a high-level overview of science results, the post-mission review paper by Linda Spilker (unfortunately behind a paywall, if you're not an AAAS member) covers the principal science results, at least those that would fit within the Science journal's page limits. It includes copious references to the initial science papers reporting those results. But since the Cassini-Huygens data set (some 3 Tbits of raw downlinked data in the prime mission alone) has produced more than 4,000 science papers (!) there is no single publication or web site that covers, even summarizes, it all.
If you want the data themselves — and this is not for the faint of heart! — they're all publicly available from the Planetary Data Set, "PDS",. For Cassini the PDS organizes data by discipline, into nodes: there's an "Atmospheres" node, an "Imaging" node, a "Ring-Moon Systems" node, etc. The Atmospheres node also serves as the repository for general information about the mission that aids in accessing, reducing, or interpreting the data. That site also has many useful links to other information sources. This Planetary Society site tells how to access and use imaging data, and has some general information about the PDS, with many links, including links to an alternate data repository, the National Space Science Data Center, "NSSDC".
For Huygens data, ESA maintains a data repository at their Planetary Science Archive, "PSA". The Planetary Society site offers a link to this ESA site.