Move to new golang 1.17 build tag format "//go:build"

# Proposal

Update all current build tags `// +build` to new format accepted in [go 1.17](https://go.dev/doc/go1.17) `//go:build`.

## Reasoning

Since we've transitioned all CI tooling (Dockerfiles/etc), and go module (go.[mod|sum]) files to go 1.17, which supports this new format, we should move all of the existing tags to the new format.