H2O-3 Release Pipeline Migration to GitHub Actions

[silvarohan18]

Description

The H2O-3 release pipeline has been fully migrated from Jenkins to GitHub Actions to streamline building, signing, and publishing H2O-3 to multiple channels. The pipeline supports both manual triggers and scheduled nightly builds, with branch-specific default behavior for publishing and testing.

Key Features

• Configurable inputs: dry run, test release, credentials testing, Hadoop support, PyPI, Conda, Docker, Nexus, and Helm publishing.
• Initialization step determines branch, build number, dry run, and release mode settings.
• Optional credentials testing for AWS, PyPI, Docker Hub, and Anaconda.
• Sequential jobs for building H2O-3, creating Git tags, and publishing to S3, PyPI, Conda, Helm, and Docker.
• Detailed release summary generated at the end, including stage status, version, branch, build number, and S3 location.
• Dry run mode skips all external publishing for safe testing.

Expected Outcome

• Reliable, automated H2O-3 builds and releases with GitHub Actions.
• Clear tracking of release stages and artifacts in S3.
• Consistent behavior across branches and environments, matching previous Jenkins defaults.