Release the image with pre-built gtctl

[zyy17]

Background

For more convenient deployment, we should also support the release of the small tool image(like a distroless base image) that already has the pre-built gtctl.

[tisonkun]

Sounds reasonable. Shall we publish the image to ghcr.io?

And if we'd like to support ARM architecture, perhaps we need some self-hosted runner to build.