Add darklings-roller extension

[mvoncken]

Make sure that your submission has the following:

• [x ] A link to the raw github markdown file with a YAML front matter definition containing:
  • [ x] The title of your extension
  • [x ] A description of your extension
  • The author
  • [x ] A hero image
  • [ x] An icon
  • [x ] Tags (these will help with your extension's discoverability)
  • [x ] A link to your extensions manifest

Please, go through these steps before you submit a PR.

• [x ] You have done your changes in a separate branch.

• [ x] You have a descriptive commit message with a short title (first line).

• [x ] You have only one commit (if not, squash them into one commit).

• [x ] Your pull request MUST target the main branch on this repository.

• [ x] Your pull request puts your extensions details as the last entry in the extensions.json file

[mvoncken]

Here are 3 JSON urls for manual testing
https://shadowdarklings.net/api/json/xUMSR4HWGBB1V0w9ygzy
https://shadowdarklings.net/api/json/nP7EBv0Ep0bhvNIqxL7z
https://shadowdarklings.net/api/json/JmnPPwDOUp0hAyUFYwdF

[Several-Record7234]

Validation script and image URLs check out fine. 'Learn-more' link is fine.

Extension functionality and API usage not checked.