find a way to create static html dumps
moin 1.9 had "moin dump" to create static html dumps, but moin2 has no such feature yet.
Problem: if one wants to load such html directly from the filesystem into a browser (without using a web server), the URLs in the html need to be relative. also, the filenames need to get some appropriate extension, because there is no web server to give a content-type header.
I tried Frozen-Flask a while ago, but was unable to create relative URLs. So we could use this just for html dumps that are served at some specific URL.