Publish antctl binaries for different platforms in releases

[weiqiangt]

Describe the problem/challenge you have
The antctl binaries are not included in release publish.

Describe the solution you'd like
Publish antctl binaries for different platforms in releases.
Also publish the antctl deploy yaml and image when #310 is implemented.

Anything else you would like to add?
Need to consider the name of antctl for each platform

[weiqiangt]

Hi @antoninbas, it looks like binaries in the release page are uploaded manually? If so, I think there is no change that should be involved in the repo?
I see Kind publishes binaries for different platforms in the form kind-{platform}, could we also follow this style?

[antoninbas]

@weiqiangt @lzhecheng

yes I will take care of publishing the antctl binaries for linux / macOS / windows for upcoming releases

we do not publish any binary at the moment, just the antrea manifest, but that will change starting with 0.3.0

it will be manual at first (I'll add a script to the repo, a bit like what Kind does), but we can look into automating it later (maybe using something like goreleaser as a starting point?)

[antoninbas]

We discussed this at the 01/22/2020 Antrea community meeting. We decided to postpone publishing the binaries until the next release for 2 reasons:

• no available user-facing documentation yet (see Document antctl #337)
• the only "useful" command that may be part of the release (agent-info - Implement antctl agent-info #318) can only be run locally from within the agent Pod. Since the Antrea docker container already includes the antctl binary, there is really no need to distribute a binary with the release as well. When antctl provides some useful commands that can be run from out-of-cluster, we can reconsider