feature: support array with shapely geometries in `GeospatialUtils`

[dbrakenhoff]

Is your feature request related to a problem? Please describe.
From discussion in #2646, shapely supports operations on numpy arrays with geometries, but these are not really supported by GeoSpatialUtil.

Describe the solution you'd like

import shapely
from flopy.utils.geospatial_utils import GeoSpatialUtil

x = np.ones(100)
y = np.ones(100)
pts = shapely.points(x, y)

gu = GeoSpatialUtil(points)
gu.shapely  # np.array of points

Currently the above code raises AssertionError: shapetype must be one of the following:

This will allow users to pass arrays of geometries to GridIntersect operations.

[dbrakenhoff]

Solved within the GridIntersect class in #2657