OIDC: use `oidc-client-ts` (#3544)
* use oidc-client-ts during oidc discovery
* export new type for auth config
* deprecate generateAuthorizationUrl in favour of generateOidcAuthorizationUrl
* testing util for oidc configurations
* test generateOidcAuthorizationUrl
* lint
* test discovery
* dont pass whole client wellknown to oidc validation funcs
* add nonce
* use client userState for homeserver
