Bug fixes

• Implementing PAReview recommendations.

#2952435: Merge in the CommonMark project

• Coding Standards in css file, don't use IDs in selectors and multiple selectors should each be on a single line.

Merged Release 8.x-2.19 as it was on a different branch.

• Adding rbl check and firewall redirection to honeypot via service.
• Adding online api rbl checks for honeypot.
• Adding rbl check and firewall redirection to recaptcha via service.
• Adding online api rbl checks for recaptcha.