Added Prometheus-apb

[jparrill]

This PR contains all the Prometheus APB, included:

• Prometheus server or Prometheus server + Oauth-Proxy
• Prometheus AlertManager
• Plans Ephemeral and Persistent
• Deprovision
• APB Tests

ConfigMaps

• Some Rules for alerting prometheus-rules
• Oauth-Proxy Config: prometheus-proxy-oauth-configmap
• Prometheus server configuration: prometheus-configmap
• Prometheus-AlertManager configuration: prometheus-alertmanager-config-map
• Prometheus-AlertManager templates: prometheus-alertmanager-templates-configmap

Behaviour

By default this APB will deploy a secured (by oauth-proxy) prometheus server that will screape all the pods on the project that you want with a Service Account called prometheus-proxy or prometheus in a non-secured deployment.