feat: add experimental geoxarray reader

[vincentsarago]

ref #909

import xarray
from obstore.store import HTTPStore
from zarr.storage import ObjectStore
from affine import Affine
from rasterio.crs import CRS
from matplotlib.pyplot import imshow

from rio_tiler.experimental.xarray import GeoArrayReader

# Create Obstore Store
store = HTTPStore("https://s3.explorer.eopf.copernicus.eu/esa-zarr-sentinel-explorer-fra/tests-output/sentinel-2-l2a/S2B_MSIL2A_20260216T142149_N0512_R096_T25WFV_20260216T165051.zarr")
zarr_store = ObjectStore(store=store, read_only=True)
dt = xarray.open_datatree(
    zarr_store,
    engine="zarr",
    create_default_indexes=False,
    consolidated=True,
)

ds = dt["/measurements/reflectance/r720m"]

attributes = ds.attrs

tr = attributes["spatial:transform"]
transform = Affine(*tr)
crs = CRS.from_user_input(attributes["proj:code"])

with GeoArrayReader(ds["b02"], transform=transform, crs=crs) as dst:
    img = dst.preview()