Signup abuse detection and blocking 1.16.8

• Add "Allow rejected user logout" option

• Fix the moderate based off threshold was incorrectly using reject threshold instead of moderation threshold (affects v1.9.1-1.9.3)

• As documented, make ASN matching actually stop on first match
• As documented, make Allowed email domain matching actually stop on first match

• Fix Link Checker not being run on post contents

• Fix allowing banned users to logout was failing
• Inject a "log out" link onto banned error page if "Allow banned logout" is true
• Force global namespace for functions which are known to be optimizable to bytecode in php

• Use <xf:fa icon="..." /> instead of hard-coded icons
• Ensure multi-account tracking isn't triggered from an admincp login
• Correctly set tracking cookie on logout & keep-alive ping (previous code was ineffective as it had the wrong cookie path)
• Capture client timezone & language into user registration log
• Add filtering for allowed email domains in admincp

• Fix 'no javascript' not working for external account association
• Fix multi-account detection not working for external account association
• Work-around for default reject reason phrase (spam_prevention_registration_rejected) being too long causing a 'string too long' phrase instead of the reject reason

• Link spam checker now captures [media] embeds. If exists, the bb-code media site url is used otherwise the media embed is rendered and then any url(s) extracted

• Improve User Registration log filtering

• Fix error when doing email pattern check on registration