curvefs supports multiple s3 in one fs

[Cyber-SiKu]

Description

Currently the data of curvefs is stored in S3 and one fs corresponds to one S3 bucket. The download bandwidth of the entire fs is limited by the download bandwidth of a single bucket.
In order to improve download bandwidth, a fs needs to support multiple S3 buckets. And it allows deployment in different S3 services (such as NOS, minio, OSS, etc.).

Proposed solution

Hash the S3 object into the S3 bucket, s3info Add a key to indicate which s3 bucket .
Add this key before the name of the s3 object to indicate the s3 bucket it belongs to.