Kubernetes: run adminer on a cloud machine via k8s.

[YuryHrytsuk]

          Task: Run `adminer` on a cloud machine via k8s.

Originally posted by @mrnicegyu11 in #618 (comment)

### Tasks
- [x] Install k8s cluster with kubespray
- [x] Run k8s locally
- [x] Expose adminer through NodePort (locally)
- [x] Run traefik + expose dashboard (locally)
- [x] Expose adminer through traefik (locally)
- [x] Find a solution to properly expose traefik on clusters ([SO question](https://stackoverflow.com/questions/78522036/how-to-use-kubernetes-with-existing-aws-nlb))
- [x] Run traefik + adminer on a real k8s cluster in cloud
- [x] Configure cert management
- [x] Write minimal deploy CI to use
- [x] Switch to k8s adminer

[YuryHrytsuk]

Literature / Sources

• https://helm.sh/docs/intro/cheatsheet/
• traefik helm chart doc
• nginx ingress controller from k8s

[YuryHrytsuk]

Questions

How to manage charts

• install charts via repos (i.e. helm repo add <repo-name> && helm install <chart-name> <repo-name>
• or we install charts form file system (i.e. helm install <chart-name> ./mychart)

---

How to implement ENV ingestion with helm?

• https://stackoverflow.com/questions/49928819/how-to-pull-environment-variables-with-helm-charts
• https://stackoverflow.com/a/60098256 (makes sense but does not utilize k8s secrets)

[YuryHrytsuk]

Ingress vs. LoadBalancer vs. NodePort

An Ingress does not expose arbitrary ports or protocols. Exposing services other than HTTP and HTTPS to the internet typically uses a service of type Service.Type=NodePort or Service.Type=LoadBalancer.
source: https://kubernetes.io/docs/concepts/services-networking/ingress/