There is no such thing, yet
to even make something like this would require there to be some way to format/organize this. As far as I know Ive never heard of a standardized structure to world building and if there is it must be annoyingly complicated and overly rigid.
Thus at this point you gotta use some kind of generic collaborative document generation tool.......like google docs.
Great thing about google docs is it has version history so if someone flips the table on your project you can just revert their changes.
1.Collaborative
google docs
2.Web based
google docs
3.Ability to include texts and images (maps and illustrations)
google docs
4.Easy to use
google docs is a google product, just about one of the few companies with a significant track record on ease of use.
5.Somehow secure (not allowing a bad-faith collaborator delete all contributed material)
on google docs you can whitelist your contributors preventing some troll from showing up and wrecking everything. You can also revert changes using the revision history.
and that can give a formatted book as an output
Sure google docs can do that too....though again the formatting is going to be on you.
I only suggest this next thought because it would be such a proper, fun even, way to really collaboratively attack building a world.
Now if you want a real approach to collaboratively building a world. You can repurpose an agile tool like JIRA, plot your high level target world ideals as epics and pose research questions as stories that you pass off to willing team mates that link to a google doc where the answer is built.
This way you organize and distribute your world building in a trackable way. providing this kind of structure would actually stimulate and focus collaborative effort. The down side is if you are unfamiliar with agile and agile tools this would be a pain in the ass to figure out.