Allow optionally to disable range caching. (#9908)

The default behavior is to cache each range requested
to cache drive. Add an environment variable
`MINIO_RANGE_CACHE` - when set to off, it disables
range caching and instead downloads entire object
in the background.

Fixes #9870

cmd/config/errors.go

@@ -96,6 +96,12 @@ var (
 		"MINIO_CACHE_ENCRYPTION_MASTER_KEY: For more information, please refer to https://docs.min.io/docs/minio-disk-cache-guide",
 	)
 
+	ErrInvalidCacheRange = newErrFn(
+		"Invalid cache range value",
+		"Please check the passed value",
+		"MINIO_CACHE_RANGE: Valid expected value is `on` or `off`",
+	)
+
 	ErrInvalidRotatingCredentialsBackendEncrypted = newErrFn(
 		"Invalid rotating credentials",
 		"Please set correct rotating credentials in the environment for decryption",