Re-alias Alloy to upstream

Alloy was created before the upstream syntax was fully decided upon by the VS. We need to adjust this package to be compliant with that standard.

Essentially, we need to change:

dependencies:
  - name: k8s-monitoring
    version: "3.2.1"
    repository: https://grafana.github.io/helm-charts

to:

dependencies:
  - name: k8s-monitoring
    version: "3.2.1"
    repository: https://grafana.github.io/helm-charts
    alias: upstream

And adjust all values inside the package, the documentation, and the Big Bang umbrella to reflect this change as well as ensuring this does not create any issues.