Contrib:gitpod-image: remove dependency on Helm chart

[meysholdt]

Is your feature request related to a problem? Please describe

As a preparation to delete the Helm chart (#9842), we should remove the dependency to the helm chart from contrib/docker/gitpod-image.

Example References:

gitpod/contrib/docker/gitpod-image/gitpod-helm-installer.yaml

Lines 51 to 54 in dbc5805

	echo "Installing Gitpod from charts.gitpod.io"
	helm repo add gitpod https://charts.gitpod.io
	helm repo update
	helm install gitpod gitpod/gitpod --timeout 60m --values /root/install/values.yaml

Proposed Solutions

a) Migrate the example to the installer
b) Delete the example

[lucasvaltl]

Not relevant anymore because the image already does not exist anymore.