Fix github pages

[daymxn]

Fixes the github pages deployment:

• working-directory doesn't apply to uses- only run, so we need to add the wiki/ prefix manually to the upload artifacts step
• since we're using a custom domain, we should use an empty baseurl.
• add a CNAME file in the static dir according to the the docs

I might be missing something, but lets throw it at the wall and see how it goes