Add openreview link and update steam link format

[Z1zs]

@RayeRen Hi~ Steam has changed its user link to https://steamcommunity.com/profiles/{{ author.steam }}, and the old link https://steamcommunity.com/id/{{ author.steam }} can not be opened correctly. So I changed the steam link format in _includes/author-profile.html.

I have also add a link for openreview in author-profile as well as _config.yml, since openreview.net has been widely used for paper reviewing, especially for computer science domain.