Add owl20 extension

[mvoncken]

Make sure that your submission has the following:

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

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

• You have done your changes in a separate branch.

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

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

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

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

[mvoncken]

I would like to include video, would that webm image in my current store.md work?

[Several-Record7234]

Validation script and image URLs check out fine.

Extension loads OK, no dev console warnings/errors, but functionality and API usage not checked.

[Several-Record7234]

I would like to include video, would that webm image in my current store.md work?

@mvoncken I believe so, but now that I've tagged Nicola in, she can confirm!

[mvoncken]

Several-Record7234

I changed it from video to gif, ready for final review,