[Feature]: X-Y plot

### Problem to solve

Currently all plots are time series, however often one wants to plot two parameters in an X-Y plot to see if there is a correlation (or not) between the two variables, or even to quantify this to some extend.
An example is temperature motor versus RPM of the motor, or CO2 concentration versus humidity etc.

### Proposed solution

X-Y plot
- autoscaling vs manual scaling
- determine correlation coefficient - see https://github.com/RobTillaart/Correlation
- auto-trailing - show all points versus last N
- keep extrema - ON OFF in the graph

### Alternatives considered

Libreoffice calc / Excel

### Area of the app

Plot rendering

### Willingness to contribute

- [ ] I'd be willing to submit a PR for this
- [x] I can help test and provide feedback

### Additional context, screenshots or mockups

_No response_