Python: Add overture buildings example #2091

Job	Run time
build-benchmarks	3m 10s
check-features-with-external-dependencies (-F gdal -F gdal/bindgen)	2m 18s
Lint and Test	7m 55s
check-features-with-external-dependencies (-F geos)	38s
check-features	1m 5s
check-features-with-external-dependencies (-F proj)	1m 5s
check-features (-F csv)	1m 11s
check-features (-F flatgeobuf)	48s
check-features (-F flatgeobuf_async)	1m 10s
check-features (-F ipc_compression)	1m 21s
check-features (-F parquet)	56s
check-features (-F parquet_async)	55s
check-features (-F parquet_compression)	2m 7s
check-features (-F polylabel)	1m 3s
check-features (-F postgis)	1m 0s
check-features (-F rayon)	51s
	27m 33s

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