Consider using geopandas for iceflow dataframes

[trey-stafford]

I am not sure we can use geopandas directly for ITRF transformations, but we can at least make the dataframes geo-aware. E.g., this works:

>>> from pathlib import Path
>>> from nsidc.iceflow.data import glah06


>>> filepath = Path("downloaded-data/GLAH06/GLAH06_634_1102_001_0072_1_01_0001.H5")
>>> result = glah06.glah06_data(filepath)
>>> geodf = gpd.GeoDataFrame(result, geometry=gpd.points_from_xy(result["longitude"], result["latitude"], crs="ITRF2008"))

>>> geodf.crs
<Geographic 2D CRS: EPSG:8999>
Name: ITRF2008
Axis Info [ellipsoidal]:
- Lat[north]: Geodetic latitude (degree)
- Lon[east]: Geodetic longitude (degree)
Area of Use:
- name: World.
- bounds: (-180.0, -90.0, 180.0, 90.0)
Datum: International Terrestrial Reference Frame 2008
- Ellipsoid: GRS 1980
- Prime Meridian: Greenwich