finish draw-polygon mode cartesian and add tests

[eKerney]

Finished updating draw-polygon-mode.ts to use turf(geo modes), and simple geometric functions(cartesian modes). Did not attempt turfJS kinks function which involves another order of complexity. Created simple geometry functions and tests, needed to bypass linter checks for complexity on validateAndCreateHole().

[marcomuser]

Fantastic! I just stumbled over a similar issue with the ThreeClickPolygonMode. That would also need a cartesian handling. Are you planning to handle the other modes as well in future PRs?

I'm currently subclassing that mode to make it work with cartesian layers:

class CartesianDrawRectangleUsingThreePointsMode extends DrawRectangleUsingThreePointsMode {
  override getThreeClickPolygon(
    coord1: number[],
    coord2: number[],
    coord3: number[]
  ) {
    const [x1, y1] = coord1;
    const [x2, y2] = coord2;
    const [x3, y3] = coord3;

    const ex = x2 - x1;
    const ey = y2 - y1;
    const len = Math.sqrt(ex * ex + ey * ey);
    if (len === 0) return null;

    const px = -ey / len;
    const py = ex / len;
    const d = (x3 - x1) * px + (y3 - y1) * py;

    const p3 = [x2 + d * px, y2 + d * py];
    const p4 = [x1 + d * px, y1 + d * py];

    return {
      type: 'Feature' as const,
      properties: { shape: 'Rectangle' },
      geometry: {
        type: 'Polygon' as const,
        coordinates: [[coord1, coord2, p3, p4, coord1]],
      },
    };
  }
}