And the answer is…
You need to do your own research. ??
I’m trying to say that as nicely as I can, because I don’t mean it to sound rude, dismissive, or like we’re not willing to help. The biggest thing is that everyone has their own ways of doing things, so even though you say that you want a site like that, I’m 100% sure that you don’t want it exactly like that. That’s why it’s you that really needs to look through what’s available, and see what meets your own individual needs.
One thing to remember as well is that with sites like that, they usually end up using a lot of cusotm-buitl code, so no matter what you do you won’t find anything in the repository that iwll match exactly what it does. That means that you’ll have ot be doing the same sort of custom work yourself.