First part of registration selenium test

Signed-off-by: Michal Čihař <michal@cihar.com>
Complete test for registration

Signed-off-by: Michal Čihař <michal@cihar.com>
Split registration code to be reusable

Signed-off-by: Michal Čihař <michal@cihar.com>
Correctly handle messages with more tags

Signed-off-by: Michal Čihař <michal@cihar.com>
Test failed registration without cookies (issue #518)

Signed-off-by: Michal Čihař <michal@cihar.com>