Add methods to request access token synchronous

[TizioIncognito]

[filipkowicz]

in kotlin you can easily do it with extension and suspendable method:

internal suspend fun AuthState.performActionWithFreshTokens(service: AuthorizationService): String =
        suspendCancellableCoroutine { cont ->
            performActionWithFreshTokens(service) { accessToken, idToken, ex ->
                if(accessToken != null) {
                    cont.resume(accessToken)
                } else {
                    cont.cancel(ex)
                }
            }
        }