Docs add rustac quickstart

[aboydnw]

Draft rustac quickstart notebook: filter, export, and GeoPandas-bridge Sentinel-2 items from the GeoParquet snapshot.

Related to the tutorial pr here: microsoft/PlanetaryComputerDataCatalog#533

[gadomski]

Since this is a rustac tutorial, we can use rustac to search as well.

[gadomski]

I think it calls them "part" a couple other places as well, should be partition.

Suggested change

	"Point `search()` at the snapshot glob and pass the filters you want pushed into the read, so only matching rows cross the network. The glob (`/*.parquet`) spans the monthly part files.",
	"Point `search()` at the snapshot glob and pass the filters you want pushed into the read, so only matching rows cross the network. The glob (`/*.parquet`) spans the monthly partition files.",

[gadomski]

It might be useful to list the partition files, e.g. with obstore.

from obstore.auth.planetary_computer import PlanetaryComputerCredentialProvider
from obstore.store import AzureStore

store = AzureStore(
    credential_provider=PlanetaryComputerCredentialProvider(
        "https://pcstacitems.blob.core.windows.net/items"
    )
)
for list_stream in store.list(prefix="sentinel-2-l2a.parquet"):
    for object_meta in list_stream:
        print(object_meta)

[gadomski]

We can get a count of the number of parquet files from the obstore list that I suggest above.

Suggested change

	"`DuckdbClient.search` is synchronous (no `await`); the bundled engine scans the part files for you, which takes a little time on the first call.",
	"`DuckdbClient.search` is synchronous (no `await`); this is a search over X parquet files without an index, so expect it to take a couple of minutes.",

[gadomski]

Since we're narrowing the datetime, we could show how you can speed up the query by narrowing the glob to something like az://items/sentinel-2-l2a.parquet/part-*_2017-*.parquet.

[gadomski]

I don't know what "looks public" means.

Suggested change

	"The account name looks public, but reads still need a SAS token. The high-level `rustac.search()` coroutine cannot pass Azure credentials, so use `rustac.DuckdbClient` instead and configure its connection once: fetch a container SAS from the Planetary Computer token API, register an Azure secret, and switch the Azure transport to curl.",
	"Reading from the account needs a Shared Access Signature (SAS) token. The high-level `rustac.search()` coroutine cannot pass Azure credentials, so use `rustac.DuckdbClient` instead and configure its connection once: fetch a container SAS from the Planetary Computer token API, register an Azure secret, and switch the Azure transport to curl.",

[gadomski]

Suggested change

	"If every cell above ran, you pushed a spatial, temporal, and cloud-cover filter into a remote GeoParquet snapshot, read back only the matching Sentinel-2 scenes, wrote them to Parquet, and bridged them into GeoPandas: STAC-GeoParquet \u2192 filtered Arrow table \u2192 GeoDataFrame, with no full download.",
	"If every cell above ran, you used a spatial, temporal, and cloud-cover filter to read matching Sentinel-2 scenes, wrote them to Parquet, and bridged them into GeoPandas: STAC-GeoParquet \u2192 filtered Arrow table \u2192 GeoDataFrame.",