Use Goreleaser to publish releases

[ofalvai]

Context

Use Goreleaser for building the release binaries of envman. The current bash scripts and workflows that build and publish the binaries to GitHub are error prone and the entire release workflow is defined at multiple places (bitrise.yml in the repo, Bitrise project of envman, the tooling-control-center project).

This PR simplifies the workflow and defines the entire process as source files in the repo (so that we can keep track of changes)

Changes

• Create Goreleaser config file as .goreleaser.yml
• Build arm64 and amd64 binaries for Linux and macOS (just like before)
• Use Goreleaser to create the changelog and publish a GitHub release. This was previously defined in the tooling-control-center workflow
• Test the release process in the PR validation workflow by creating a snapshot release (without publishing)