Unnecessary use of GitHub API for management cluster Flux bootstrap

[rizblie]

Current instructions for GitHub Flux bootstrap requires the use of a GitHub PAT. This is because the bootstrap is being performed using the GitHub API i.e. using flux bootstrap github.

This can be avoided by using the Git protocol with the existing ssh key instead of the GitHub API e.g.

flux bootstrap git \
  --url=ssh://git@github.com/rizblie/gitops-system.git \
  --private-key-file=/home/ubuntu/.ssh/gitops \
  --components-extra=image-reflector-controller,image-automation-controller \
  --namespace=flux-system \
  --branch=main \
  --path=clusters/mgmt

This is a more generic solution as it does not rely on a GitHub-specific API and can be used with other Git hosting services.