feat: Add geometry validation to GeoJSON validator (Phase 1)

Implements coordinate range validation, geometry type checking, and structure validation for all GeoJSON geometry types as specified in Issue camptocamp#72.

- Add validatePosition() for coordinate range checking (lon: -180 to 180, lat: -90 to 90)
- Add validators for Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon
- Integrate geometry validation into all 7 CSAPI feature validators
- Add 27 comprehensive geometry validation tests

Closes Sam-Bolling/CSAPI-Live-Testing#72

Author: Sam-Bolling