add from_attrs class method to construct object without type attribute

[vincentsarago]

another take at #171 and #174

This PR adds a from_attrs(cls, **kwargs: Any) classmethod to Feature/FeatureCollection and geometries Object to enable Object creation with partial attributes (e.g without type={object type}).

from geojson_pydantic import Point

Point.from_attrs(coordinates=[0,0])
>> Point(bbox=None, type='Point', coordinates=Position2D(longitude=0.0, latitude=0.0))

Point.from_attrs(type="Point", coordinates=[0,0])
>> Point(bbox=None, type='Point', coordinates=Position2D(longitude=0.0, latitude=0.0))

Point.from_attrs(type="P", coordinates=[0,0])
ValidationError: 1 validation error for Point
type
  Input should be 'Point' [type=literal_error, input_value='P', input_type=str]
    For further information visit https://errors.pydantic.dev/2.11/v/literal_erro

I've not added type information on kwargs to make sure the method could work with subclasses

NOTE: I'm open to class method name if from_attrs doesn't make sense

cc @kopp @geospatial-jeff @frank-hulo @gadomski