A way to extend visualization charts with custom components

**Is your feature request related to a problem? Please describe.**
In doing data analysis, it can be useful to visualize simple linear relations in scatterplots. I couldn't find something like that in PygWalker documentation.

**Describe the solution you'd like**
A template or a way to register new chart components (or are they called elements? in this case a matplotlib chart) to the existing ones

**Describe alternatives you've considered**
None so far, I have little expertise in Streamlit extensions

**Additional context**
None

Start by reading the PygWalker documentation and examining how its existing chart components are defined. Then investigate the Streamlit extension approach and the matplotlib chart integration mentioned in the request. Done would mean having a decided, documented way to register a custom chart component, with a template or example.

Written by the indexing model from the issue text.