allow file separated band storage

[vincentsarago]

closes #18

with CMRBackend() as backend:
    assets = backend.assets_for_tile(
        x=116,
        y=78,
        z=7,
        limit=1,
        concept_id="C2021957657-LPCLOUD",
        temporal=("2024-02-11", "2024-02-12")
    )
assets
>> [{'url': 's3://lp-prod-protected/HLSL30.020/HLS.L30.T55HEV.2024042T000309.v2.0/HLS.L30.T55HEV.2024042T000309.v2.0.B01.tif',
  'provider': 'LPCLOUD'}]

with CMRBackend() as backend:
    assets = backend.assets_for_tile(
        x=116,
        y=78,
        z=7,
        limit=1,
        bands_regex="B[0-9][0-9]",
        concept_id="C2021957657-LPCLOUD",
        temporal=("2024-02-11", "2024-02-12")
    )
assets
>> [{'url': {'B01': 's3://lp-prod-protected/HLSL30.020/HLS.L30.T55HEV.2024042T000309.v2.0/HLS.L30.T55HEV.2024042T000309.v2.0.B01.tif',
   'B10': 's3://lp-prod-protected/HLSL30.020/HLS.L30.T55HEV.2024042T000309.v2.0/HLS.L30.T55HEV.2024042T000309.v2.0.B10.tif',
   'B02': 's3://lp-prod-protected/HLSL30.020/HLS.L30.T55HEV.2024042T000309.v2.0/HLS.L30.T55HEV.2024042T000309.v2.0.B02.tif',
   'B06': 's3://lp-prod-protected/HLSL30.020/HLS.L30.T55HEV.2024042T000309.v2.0/HLS.L30.T55HEV.2024042T000309.v2.0.B06.tif',
   'B03': 's3://lp-prod-protected/HLSL30.020/HLS.L30.T55HEV.2024042T000309.v2.0/HLS.L30.T55HEV.2024042T000309.v2.0.B03.tif',
   'B11': 's3://lp-prod-protected/HLSL30.020/HLS.L30.T55HEV.2024042T000309.v2.0/HLS.L30.T55HEV.2024042T000309.v2.0.B11.tif',
   'B09': 's3://lp-prod-protected/HLSL30.020/HLS.L30.T55HEV.2024042T000309.v2.0/HLS.L30.T55HEV.2024042T000309.v2.0.B09.tif',
   'B05': 's3://lp-prod-protected/HLSL30.020/HLS.L30.T55HEV.2024042T000309.v2.0/HLS.L30.T55HEV.2024042T000309.v2.0.B05.tif',
   'B04': 's3://lp-prod-protected/HLSL30.020/HLS.L30.T55HEV.2024042T000309.v2.0/HLS.L30.T55HEV.2024042T000309.v2.0.B04.tif',
   'B07': 's3://lp-prod-protected/HLSL30.020/HLS.L30.T55HEV.2024042T000309.v2.0/HLS.L30.T55HEV.2024042T000309.v2.0.B07.tif'},
  'provider': 'LPCLOUD'}]

In the endpoints this PR add two new options:

• bands: e.g B01 key to use to specify the file url
• bands_regex: e.g B[0-9][0-9], regex expression to use to find the band name in the URL

cc @sharkinsspatial