Fix spelling of "superscript"
***NO_CI***

+ Remove duplicated await
+ Replace some legacy codes with ES6
+ Fix some of eslint problems

* fix: secure html module removes allowfullscreen, allow and frameborder attributes from iframes
* Apply suggestions from code review
fix: remove deprecated attributes for iframe in secure html module
Co-authored-by: Nicolas Giard <github@ngpixel.com>

* feat: Caching kroki svgs #2020

* fix: no markdown support for underline #2072

* feat: Kroki integration

see https://kroki.io/

* fix: markdown-kroki def updates
Co-authored-by: Nicolas Giard <github@ngpixel.com>

* #1853: XSS attack fix by adding rel noferrer or rel noopen to _blank target external links

* fix: relAttributeExternalLink noopener
Co-authored-by: danallendds <daniel.allen@friends.dds.mil>
Co-authored-by: Nicolas Giard <github@ngpixel.com>