Active Directory test should attempt to use "Test" button

All tests attempt to use the "test" button before setting security.
When test button fails, the test should exit without touching the
security realm.
Update scenarios in tests javadoc
This should be part of corresponding `PageArea` (not `PageObject`) as there may be zero to many test/validate buttons on a page. Aside from that, those buttons use various captions and report success/failure differently which is something only page area should be aware of. See `MailerGlobalConfig#sendTestMail`.