The zipfile you download from Facebook is already in the correct format. All you need to do it spin up a web server (apache nginx etc.) and unzip the files into the webroot.
For security, just add the usual webserver/*nix security.
EDIT: Just unzipped an old download from my (pre-purged) profile into an empty web folder, and it all works, mostly. FB specific icons are missing, and your private messages are all in a subfolder called 'messages' which has no security, and all the threads are folded into a long chronological list. So I guess the format would need tweaking a bit.