GEOT-4566 Obtain complete GeoJSON FC schema

Added a new method to FeatureJSON to obtain the a feature collection schema by reading all features in search of the data types of all properties.

FeatureJSON#readFeatureCollection schema reads the {@link SimpleFeatureType} of a GeoJSON using FeatureTypeHandler, which is simpler handler when compared to FeatureHandler. In the  worst case, it will parse all features searching for attributes not present in previous features.
Merge pull request #267 from williamvoor/GEOT-4566

[GEOT-4566] Obtain complete GeoJSON FC schema