base_shape input to GeomCollector extends the domain

[SorooshMani-NOAA]

Base shape input for collector-type geometry object is supposed to clip off excess of domain, however right now it adds to the domain if pars of it fall outside of the input rasters:

[SorooshMani-NOAA]

The issue seems to be due to the fact that the base shape is taken as the "exterior boundary" in the combine_geom logic:

OCSMesh/ocsmesh/ops/combine_geom.py

Lines 144 to 155 in 88aed38

	if base_mult_poly:
	# NOTE: This needs to happen once and before any
	# modification to basemesh happens (due to overlap
	# w/ DEM, etc.). Exterior of base mesh is used for
	# raster clipping
	#
	# TODO: Add buffer for base mesh exterior in case there
	# was erosion and we want to make sure new DEMs futher
	# inland are considered (?)
	self._base_exterior = MultiPolygon(
	list(ops.polygonize(
	[poly.exterior for poly in base_mult_poly.geoms])))