Override default chart values when installing Prometheus via Kubernetes integration

Problem to solve

Currently there is no way to override Prometheus chart default settings when installing through GitLab's Kubernetes integration.

Intended users

Further details

1. The default chart scrapes 1 our of 33 possible kubernetes endpoints, as a user I'd like to specify which additional endpoints to scrape
2. As I user I'd like to specify which certificate/endpoint to use for SSL
3. As I user I'd like to specify which host name to use for this prometheus instance
4. As I user I'd like to remove persistent storage for applications that don't need it

Proposal

Allow user to specify an overide.yml file when installing prometheus

Example

alertmanager:
  persistentVolume:
    enabled: false
server:
  persistentVolume:
    enabled: false
  ingress:
    enabled: true
    tls:
      - secretName: example-tls
        hosts:
          - prometheus.example.com
    hosts:
      - prometheus.example.com

Permissions and Security

Documentation

What does success look like, and how can we measure that?

Links / references