Add some very thin UI that allows adding and renaming custom widgets

### Your use case

#### What would you like to do?
adding "custom" widgets (embedded websites) results in error 403s for other users frequently (not sure why) with scalar's "add custom widget" function. it is also possible to simply embed any page as an iframe without a manager.
you can use `/addwidget` to add them and devtools to rename them, but it would be cool if that was more accessible.

#### Why would you like to do it?
- devtools are not easy to use
- don't need an integration manager and its terms and stuff (also it's transparent what website is embedded this way)

#### How would you like to achieve it?
it would be nice if element had some UI around widgets without an integration manager.

### Have you considered any alternatives?

_No response_

### Additional context

_No response_