feat: Add elastic ip for Grafana

[rossf7]

What type of PR is this?

kind/feature

What this PR does / why we need it:

This creates an Equinix elastic IP named monitoring and assigns it to the node where Grafana is deployed.

This will allow us to request a DNS record for green-reviews.tag-env-sustainability.cncf.io

Which issue(s) this PR fixes:

Towards #31

Special notes for your reviewer (optional):

• Elastic IPs are not automatically added so this is done using netplan since the machines run Ubuntu
  https://deploy.equinix.com/developers/docs/metal/networking/elastic-ips/#host-ip-configuration
• The elastic IP is also configured with K3s by setting the --node-external-ip flag
  https://docs.k3s.io/cli/agent#networking
• With this Grafana is accessible in my test cluster at the external IP

k get no -o wide
NAME                              STATUS   ROLES                  AGE   VERSION        INTERNAL-IP     EXTERNAL-IP     OS-IMAGE             KERNEL-VERSION      CONTAINER-RUNTIME
green-reviews-worker-falco-a      Ready    <none>                 26m   v1.29.0+k3s1   147.28.133.63   <none>          Ubuntu 22.04.4 LTS   5.15.0-94-generic   containerd://1.7.11-k3s2
green-reviews-worker-internal-1   Ready    <none>                 25m   v1.29.0+k3s1   147.28.134.59   147.28.133.50   Ubuntu 22.04.4 LTS   5.15.0-94-generic   containerd://1.7.11-k3s2
green-reviews-control-plane       Ready    control-plane,master   28m   v1.29.0+k3s1   147.28.134.47   <none>          Ubuntu 22.04.4 LTS   5.15.0-94-generic   containerd://1.7.11-k3s2

[rossf7]

@nikimanoledaki @AntonioDiTuri Like we discussed I've updated to use a global IP for the elastic IP. In case we want to move region for the cluster for #4

[leonardpahlke]

LGTM. At some point we may want to move the scripting out of openTofu and into Ansible or some other tool that is better suited for this kind of job.

[leonardpahlke]

Feel free to merge whenever

[guidemetothemoon]

LGTM, thanks! 😊

[rossf7]

@leonardpahlke Yes, unfortunately the elastic IP isn't added automatically. So more bash was needed than I'd prefer.

Good idea to revisit this when we have more time.