Implement Appender Support

[Xuanwo]

We need to implement appender for supported projects.

Roadmap

• Add append-offset in specs
  • object: Add AppendOffset specs#34
• Add appender test in go-integration-tests
• Implement appender for supported services (? means we need to check whether this service support append or not)
  • azblob Add appender support go-service-azblob#18 Implement commitAppend go-service-azblob#19
  • cos (confirmed that not support)
  • dropbox (wait the proposal proposal: Make Delete idempotent #551)
  • fs storage: Implement Appender support go-service-fs#34
  • gcs (not support https://pkg.go.dev/cloud.google.com/go/storage)
  • kodo (confirmed that not support)
  • oss Implement appender support go-service-oss#15 Implement commitAppend go-service-oss#18
  • qingstor Add appender support go-service-qingstor#40
  • s3 (confirmed that not support)
  • uss (confirmed that not support)
• Add CommitAppend into go-integration-tests

[Xuanwo]

Great Work!