[Feature] Added functionality to view the email subscriber blacklist

[Improvement] Enhanced error messages if new subscriber is blacklisted

[Improvement] Improved the efficiency of the email blacklist system

[Improvement] Optimized page load for various dashboard views

[Improvement] Added new Azure datacenter locations

[Fix] Updated the Frankfurt location with correct geo coordinates

[Fix] Fixed a validation issue that allowed invalid characters in the email sender FROM name

[Fix] Fixed inbound email processing delays

[Fix] Fixed an issue in inbound email processing where certain mail clients (ie. Outlook, Yahoo) add special characters to the email address

[Fix] Fix an issue where custom metrics with no received data were causing the display settings (auto value calculations, hide Y-axis) to not be applied to other metrics on the page

[Improvement] Added the ability to require a reCAPTCHA for notification subscribers

[Improvement] Automatically use the message subject defined in the custom templates if the message_subject parameter is not defined in API requests

[Improvement] Various interface improvements in the Dashboard

[Fix] Remediated an XSS issue for incident and maintenance page views

[Fix] Remediated an XSS issue for managing notification subscriptions

[Fix] Resolved an issue where the metric chart would ignore the configured time zone and only display the times in UTC

[Improvement] Added search functionality for subscriber lists

[FIX] Fixed XSS bug for manage subscriptions

[Fix] Fixed formatting issue where a leading space was added to infrastructure names

[Improvement] Added changelog notifications in the Dashboard

[Improvement] Provide feedback when validating the affected infrastructure for new incidents and maintenances

[Improvement] Changed the post button to prevent duplicates when creating or updating incidents and maintenances

[Fix] Added validation for time values when scheduling new maintenances