[Feature] Signature Pad Widget

## Summary
Widget that allows drawing on canvas using touch or a mouse pointer

## Motivation
It could be used as a signature pad input for forms
Should support touch (mobile screens) since that would be a primary use-case

## Additional Context
Quoting from discord:
```
...was wondering if there's a way to have a signature pad... I.e. a place holder where the form user can
scribble a signature especially on a smart phone screen
```

[Front conversations](https://app.frontapp.com/open/top_96b64)