Add Steam support

[LumiFae]

Steam auth is quite easy from my own testing. This would be quite useful for Steam game servers that can be hosted by the community and then we just fetch people's steam ids from the api to get pronouns and implement it however.

I'd recommend the use of the "node-steam-openid" on NPM, but if you want to make the auth yourself then go ahead, i'm just listing an easy method.