The bitcoin.it domain is owned by the forum, but it's always had a totally independent admin team. I've never been an admin there, nor appointed any admin. However, nowadays it seems mostly abandoned, with only 5 edits in the last 30 days (about half of which look like spam); I've been thinking for a few years that I should appoint some new admins or something, or maybe just shut it down and set up a redirect to bitcoinwiki.org.
Bitcoincore.org is run by the Bitcoin Core developers. I don't know off-hand who controls it.
Thanks for the information theymos. That's all I wanted to know and I guess the community was interested as well to know about it. These domains and websites come first in the Google search. So, if it's not owned by the real community, they may spread falls information just like bitcoin.com did in the beginning by selling Bitcoin cash instead of Bitcoin. Your confirmation will remain as a document about these websites.
There is no "official" anything.
I didn't really mean that. I meant if it's owned by the forum or someone else. I know that there are no official website of Bitcoin.