Registry Auth Client

[shizhMSFT]

Registry authentication implementation for #57.

Change logs:

• Implementation authentication for the registry client.
• Resolves Registry Target #57.
• Addresses comments in Registry Client #82.
• Bump up golang version from v1.16 to v1.17 due to the use of new built-in library functions.

[deitch]

I felt like I was reading through my reimplementation of the OCI registry client in Ruby years ago, but much better done.

I do wish we could have a shared implementation of this to everyone. Now docker has one in moby, and google in ggcr, and container has one, and...

As long as this works, it is good. Maybe at one point we all can join forces?

[shizhMSFT]

As long as this works, it is good. Maybe at one point we all can join forces?

Yes, we will 😄 and oras-go has lots of advantages. It is more extensible and has fewer dependencies.

Most importantly, it will be integrated into many security products.

[SteveLasker]

great work @shizhMSFT, @deitch
High profile area always have multiple implementations. The refactoring @deitch started with @shizhMSFT have been simply marvelous!