Add test for removing cerftificate relations

[sed-i]

Issue

canonical/grafana-k8s-operator#328

Solution

Add itest for removing certificate relations.

Context

Ingress URL vs k8s fqdn vs loadbalancer IP -- which do we put in the cert?

Testing Instructions

Run integration test.
Inspect traefik's cert with e.g.

echo | openssl s_client -showcerts -connect 10.43.8.188:443 | openssl x509 -text -noout

[Abuelodelanada]

@sed-i

Please take a look at this PR: canonical/traefik-k8s-operator#354

I managed to run full cos-lite itests several times in a row without failing.

I've packed Traefik charm with that patch and used it in bundle.yaml file in cos-lite-bundle:

  traefik:
    charm: ./traefik-k8s_ubuntu-20.04-amd64.charm
    base: [email protected]/stable
    scale: 1
    resources:
      traefik-image: docker.io/ubuntu/traefik:2-22.04
    constraints: arch=amd64
    storage:
      configurations: kubernetes,1,1024M
    trust: true

With that every time I run itest @ localhost pass.

[simskij]

@Abuelodelanada @sed-i is this still relevant?