Implement Web Support for Reference Images

[Qainguin]

Add support for reference images for web import. Currently, it hides the reference image button for web users, which is more of a band-aid than anything.

[Qainguin]

I tried doing some work on this and I got to the point of where I could open the import native dialog but the problem was that loading it would not return a PackedByteArray with JavaScript but it would return a string.

[MewPurPur]

I don't know how to do this.

[Qainguin]

We might just have to shelve it for now, at least until someone knows how to. Keep the issue up though, so if someone knows how to do it they can do it.

[Kiisu-Master]

Ig this would be a task for me as i added svg opening on web

[Qainguin]

Ideally, a PR for this would also replace the JavaScriptBridge eval with get_interface to make it easier to read.