Go Client - April 3rd - added upload capability to capability package to go-libstoracha

[Goddhi]

Go Client - April 3rd - added upload capability to capability package of go-libstoracha - PLDG 2

@Goddhi

Accomplished Tasks

• added upload module in the Go-based go-libstoracha capabilities package
• implemented test on the the upload capability
• Implemented a set of upload-related capabilities including upload/*, upload/add, upload/get, upload/remove, and upload/list
• Created IPLD schema definitions for all capability data structures
• Wrote unit tests to verify serialization, deserialization, and validation of all upload capabilities
• PR link
• issue link

Update

• Awaiting PR review from either @volmedo or @alanshaw
  PR Lnk

Next Tasks

• add index capabilities to the capabilities package
• issue link