Vehicle overlay shapes

## Summary
Hi.
Id like to have the option to add custom vehicle shapes as overlay in pingviewer as this would be of great help operating large vehicles.

- Load in a list of coordinates outlining the vehicle shape.
- Fileformat could be something simple like a .csv with x and y
- Option so set colour and have multiple parts on the vehicle outline.
- Have the overlay shape scale with the selected sonar range.
- Have the overlay crop with the sonar sector setting.

I do not have enough programming knowledge to even know where to look to implement this my self.

## Additional information
Example .csv and mockup pictures so vehicle is not to scale. Assuming ping360 as CRP in the example.

```
#x,y,name,colour
-0.4,0.5,base,blue
0.4,0.5,base,blue
0.4,-1.5,base,blue
-0.4,-1.5,base,blue
-0.4,0.5,base,blue

0.3,-1.5,backpack,red
0.3,-1.8,backpack,red
-0.3,-1.8,backpack,red
-0.3,-1.5,backpack,red
```



No source files or tests are named. Start by locating Ping Viewer’s sonar display and the code handling selected range and sonar sector settings; then determine how a CSV-defined, colored multi-part vehicle outline could be loaded, scaled, and clipped. Done means the overlay can be configured from coordinate data and behaves correctly as range and sector settings change.

Written by the indexing model from the issue text.