Can't find how to add Wiki Page Library app to Public Website

Hi there.

I'm unable to add the "Wiki Page Library" app to my public facing website (Public Website). It is not in the "Site Contents > Your apps > Apps you can add" list.

Is there any way I can have a Wiki Page Library (or Enterprise Wiki) that can be accessed by anonymous users? (meaning: no login required)

My version is SharePoint Online for Microsoft Office 365 Enterprise E3 plan and I'm the admin of a trial subscription.

Thanks in advance.