Tracking issue of GSP-840: Convert to monorepo

[Xuanwo]

• GSP: #840

Roadmap

• Update mod files to v5
• Update mod name to go.beyondstorage.io
• Convert pkg/* as separate modules (Only credential and endpoint need to be spilt)
  • #843
  • #845
  • #846
• Integration tests (we need to figure how to run integration tests on a mono repo)
  • #847
• #851
• Auto releases (we can build an auto release now!)
• Dependence updates (#873)
• Update docs and examples
  • beyondstorage/site#255

Progress

• We are trying to build a demo of this mono repo.
• https://go.beyondstorage.io is online, we are ready for the repo changes.
• We will migrate all code first and then update all our workflows to meet mono repo needs
• Auto release is hard for our repo, we will find a solution for it in the futher.

[JinnyYi]

Maybe we need to update all the referenced links in docs and comments, or add a note where appropriate?