Create iframeplus.js

[kilgorezer]

iframe+ is an extension that adds to the iframe extension
wiki: https://github.com/kilgorezer/turbowarpIframeplus/wiki

[GarboMuffin]

Please open exactly one pull request and then if you want to make a change then just make the change to the pull request. Don't make a new one.

[GarboMuffin]

I blocked you for 1 day so that you have time to read the comment above and https://github.com/TurboWarp/extensions/blob/master/CONTRIBUTING.md so that you can come back tomorrow without spamming us.

[GarboMuffin]

For example, if you read the contributing guidelines, you would've seen the bolded text Your extension does not need to pass format; we will fix it for you if linting and validation pass

[GarboMuffin]

Also, the code needs to be in this repository. This loader design cannot be accepted due to unfixable issues regarding security, compatibility, maintainability, offline support, ...