fix csiro dataset access

[NekoLyn]

entry_point.py                                    AWS Batch job starts
|
+-- api = API()
|     CODataRegistry()
|       AodnDataSrc()                             public AODN bucket
|       CsiroDataSrc()                     <===== KEY REQUEST 1
|         per configured csiro.datasets entry:
|           GET key_request_url
|           --> bucket, remoteDirectory, endpoint, keys
|           GetAodn(..., s3_fs_opts=keys)         keys stored inside GetAodn (s3fs)
|
+-- api.initialize_metadata()
|     AODN catalog + CSIRO catalog merged
|     uwy_csiro.parquet now appears in the dataset map
|                                                 (this is the only thing key 1
|                                                  is used for in a batch job)
|
+-- generate_pmtiles_for_all_parquets(api, uuid)
      work = every *.parquet in the map       
      |
      api.release_memory_for_pmtiles_batch()
        self._instance = None              <===== KEY 1 THROWN AWAY HERE
                                                  no CSIRO access left in the parent
      |
      +-- Phase 1   for dataset in work:
      |     fork --> pmtiles child
      |               HexbinProcessor
      |                 DatasetScanBase.__init__          location=None, so:
      |                   resolve_dataset_location(dataset)
      |                   |     co_data_registory, NOT batch/common any more
      |                   +-- AodnDataSrc.locate_dataset  --> None   (never claims,
      |                   |                                          no network)
      |                   +-- CsiroDataSrc.locate_dataset
      |                   |     in config csiro.datasets?
      |                   |       no  --> None
      |                   |       yes --> GET key_request_url  <===== KEY REQUEST 2
      |                   |               CsiroS3Access.to_dataset_location()
      |                   +-- nobody claimed it
      |                         --> DatasetLocation(BUCKET_OPTIMISED_DEFAULT)
      |                             AODN bucket, no keys
      |                   PmTileDuckDBClient()
      |                     create_s3_secret()              AODN secret
      |                   apply_location_credentials()      CSIRO secret,
      |                                                     skipped unless
      |                                                     location.is_external
      |                 get_s3_uri()
      |                   location.parquet_glob(dataset)
      |                   --> s3://dapprd-mnf/000072626v001/data/uwy_csiro.parquet/**/*.parquet
      |               stage / geojsonseq / tippecanoe / upload --> os._exit()
      |     waitpid                                          keys die with the child
      |
      +-- Phase 2   for dataset in work:            after all pmtiles are done
            fork --> estimation child
                      EstimationIndexBuilder
                        DatasetScanBase.__init__
                          resolve_dataset_location(dataset)  <===== KEY REQUEST 3
                                                             same fan-out as above
                          PmTileDuckDBClient()      AODN secret
                          apply_location_credentials()       CSIRO secret
                      |
                      +-- small dataset (<= chunk_files)
                      |     read in this process, one statement
                      |
                      +-- big dataset, for chunk in chunks:
                            fork --> chunk grandchild
                                      reset_after_fork()
                                      PmTileDuckDBClient()   NEW connection,
                                                             AODN secret only
                                      apply_location_credentials()
                                                             CSIRO secret again
                                                             (no new HTTP - the
                                                              keys came across
                                                              the fork by COW)
                                      --> part_i.parquet --> os._exit()
                            waitpid

[HavierD]

LGTM