Implement support for login flow v2

[juliusknorr]

Currently only v1 of the login flow is supported with global scale. In order to make this work with v2 we'd need to either retrigger the login flow on the target instance or maybe cleaner, do not redirect to the target in

globalsiteselector/lib/Master.php

Lines 239 to 241 in 37051a1

	$this->logger->debug('redirectUser: direct login so forward to target node');
	$jwt = $this->createJwt($uid, $password, $options);
	$redirectUrl = $location . '/index.php/apps/globalsiteselector/autologin?jwt=' . $jwt;

but instead finish the login flow locally on the portal instance.