adjust testing environment for go:embed

Merge branch 'master' into pr/gdamjan/398

use github.com/golang-jwt/jwt

vouch#189 adfs relying_party_id minor adjustments

move the #vouch irc channel to libera.chat

vouch#375 use correct error codes, general cleanup

ignore rsa keys created for testing

Merge branch 'pr/simongottschlag/320'

bump to go version 1.16

don't log the oauth client creds, even in debug