Optimise soil AWC database update

The startup of the API always recreate the databases even if all original datasets are unchanged. Consequently, this operation lasts 3 minutes at the API start up while it could be solved in less than 5 seconds if we choose to not write soil AWC raster stacks if all sources has been taken from cache.

radis-api-1  | INFO [2025-06-18 10:16:49] Attempting to load soil AWC raster: AWCr_mm_0_200.tif (3 tries left)
radis-api-1  | INFO [2025-06-18 10:16:52] Successfully loaded soil AWC raster: AWCr_mm_0_200.tif
radis-api-1  | INFO [2025-06-18 10:16:52] Attempting to load soil AWC raster: AWCr_mm_0_200.sd.tif (3 tries left)
radis-api-1  | INFO [2025-06-18 10:16:52] Successfully loaded soil AWC raster: AWCr_mm_0_200.sd.tif
radis-api-1  | INFO [2025-06-18 10:16:52] Resampling soil AWC rasters to match extent and resolution
radis-api-1  | INFO [2025-06-18 10:17:47] Stacking soil AWC rasters
radis-api-1  | INFO [2025-06-18 10:17:47] Writing soil AWC raster stack to disk
radis-api-1  | INFO [2025-06-18 10:18:14] Soil AWC raster stack created successfully
radis-api-1  | INFO [2025-06-18 10:18:14] Attempting to load soil AWC raster: awc_mm_0_5.tif (3 tries left)
radis-api-1  | INFO [2025-06-18 10:18:17] Successfully loaded soil AWC raster: awc_mm_0_5.tif
radis-api-1  | INFO [2025-06-18 10:18:17] Attempting to load soil AWC raster: awc_mm_15_30.tif (3 tries left)
radis-api-1  | INFO [2025-06-18 10:18:18] Successfully loaded soil AWC raster: awc_mm_15_30.tif
radis-api-1  | INFO [2025-06-18 10:18:18] Attempting to load soil AWC raster: awc_mm_30_60.tif (3 tries left)
radis-api-1  | INFO [2025-06-18 10:18:18] Successfully loaded soil AWC raster: awc_mm_30_60.tif
radis-api-1  | INFO [2025-06-18 10:18:18] Attempting to load soil AWC raster: awc_mm_60_100.tif (3 tries left)
radis-api-1  | INFO [2025-06-18 10:18:18] Successfully loaded soil AWC raster: awc_mm_60_100.tif
radis-api-1  | INFO [2025-06-18 10:18:18] Attempting to load soil AWC raster: awc_mm_100_200.tif (3 tries left)
radis-api-1  | INFO [2025-06-18 10:18:18] Successfully loaded soil AWC raster: awc_mm_100_200.tif
radis-api-1  | INFO [2025-06-18 10:18:18] Stacking soil AWC rasters
radis-api-1  | INFO [2025-06-18 10:18:18] Writing soil AWC raster stack to disk
radis-api-1  | INFO [2025-06-18 10:19:38] Soil AWC raster stack created successfully