Providing a single YAML file installer

[prometherion]

Actually, we support two kinds of installation:

• Helm
• Kustomize

Kustomize is still required for the development purpose since the Kubebuilder annotations don't provide all the required extra fields, but forcing end-users to have it as installation dependency is cumbersome.

Would be great having a single YAML file that is going to be used to install all the required resources, something as kubectl apply -f https://raw.githubusercontent.com/clastix/capsule/master/config/install.yaml.

With this, we're gaining also the advantage of tracking in a more efficient way the final manifests we're using to update the Helm charts, as well tracking uncommitted changes or diff during the CI.