Add Go control plane

[eugeneo]

Note that the control plane needs to be built from the repository root, as:

docker build . -f docker/go-control-plane/Dockerfile

This is necessary to include to proto files into the build root.

[easwars]

Haven't done a full pass yet. But I thought I'll just send whatever I have for now, and will send more comments when I find time to do a complete pass. Thanks.

[eugeneo]

Thank you for the review! Did my best to address the comments.

[eugeneo]

Thanks for the review. I did my best to address the comments.

[eugeneo]

Thank you for the review. I addressed the comments.

Please note that I am working on this in parallel with #100. It is really difficult to implement changes that span both sides. I would like to check this in with the current proto files and then change the protocol once both components are checked in.

I can not implement final protocol now because I need the Python side (#100) completely setup in this repo to get access to some custom packages.

[eugeneo]

Thanks for the review! I think it is all coming together. 2 things I would like to point out:

1. Some comments I did not implement because of YAGNI. I would like to focus on merging the implementation for fallback test and not speculate about the future requirements.
2. resource.go will be removed after I implement the new API (I need to merge first).

[eugeneo]

Thanks for the review. Comments addressed.

[eugeneo]

Thanks. Addressed the comments.