Feat: Added helm chart for ElasticAgent

[supu2]

• Enhancement

What does this PR do?

Push helm chart repo to github-pages.

Why is it important?

Added Elastic-Agent helm chart for better usage of Elastic-Agent in kubernetes.

Checklist

• [x ] My code follows the style guidelines of this project
• [x ] I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in ./changelog/fragments using the changelog tool
• I have added an integration test or an E2E test
• The helm releaser need gh-pages branch.

How to test this PR locally

# Show  kubernetes resources
helm template https://github.com/supu2/elastic-agent/releases/download/elastic-agent-0.1.0/elastic-agent-0.1.0.tgz
#  Deploy Elastic-Agent to kube-system,
helm upgrade --install -n kube-system  https://github.com/supu2/elastic-agent/releases/download/elastic-agent-0.1.0/elastic-agent-0.1.0.tgz 

[cla-checker-service]

💚 CLA has been signed

[mergify]

This pull request does not have a backport label. Could you fix it @supu2? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-v./d./d./d is the label to automatically backport to the 8./d branch. /d is the digit

NOTE: backport-skip has been added to this pull request.

[elasticmachine]

Pinging @elastic/elastic-agent (Team:Elastic-Agent)

[pierrehilbert]

Thanks for contributing to our codebase.
Could you please start by signing our CLA?

[supu2]

Thanks for contributing to our codebase. Could you please start by signing our CLA?

I've signed the CLA.

[cmacknz]

Thanks for this! We know this would simplify deployment, so we are already working on this and currently have a prototype based on ECK in active development: elastic/cloud-on-k8s#7356

See #3847 for the tracking issue.

I am going to close this given this work is already in progress elsewhere, the latest update is #3847 (comment)