[discussion] Add Signature component?

*⚠️ Info: This issue is for product research, to gather community input. In this [base-ui repo](https://github.com/mui/base-ui) we are, currently, focused on the core set of components needed to create a great design system, so the probability we build this in this repo is very low.*

## Summary

## Examples in other libraries

- https://github.com/szimek/signature_pad
- https://www.telerik.com/kendo-react-ui/components/inputs/signature/
- https://retool.com/components/signature-pad
- https://budibase.com/blog/updates/2024/signature-component/
- https://github.com/agilgur5/react-signature-canvas
- https://x.com/jh3yy/status/1924961039050842561

*([internal benchmark](https://www.notion.so/mui-org/x-Signature-component-5a3602b52da9448088733200ad05d00b))*

## Motivation

TBD

- User requests:
- /
- UI library requests:
- /