Add extra Nomad Servers

Currently, a single Nomad server is orchestrating the whole Nomad cluster used for running Wind Tunnel tests. Nomad is designed to have multiple servers to make the cluster more robust and resilient.

This repo was created with the idea of expansion in mind but without implementing it. Therefore, it should be a matter of taking the [Pulumi script](https://github.com/holochain/nomad-server/blob/main/main.go) and abstracting the `nomad-server-01` parts into functions and then adding `nomad-server-02` etc.

We should also increase the value of `bootstrap_expect` in the server config.

Open questions:
1. How many servers? - I think one extra (two in total) is fine for now
2. Should we also increase the specs?
- Currently, the droplet has 4GB RAM, 2 vCPUs, and 60GB storage.
- Recommended is "4-8+ cores, 16-32 GB+ of memory, 40-80 GB+ of fast disk"
- We could just do this instead but Nomad expects multiple servers so an extra server is good.

AC:

- [ ] Make the Nomad-Server-specific code reusable
- [ ] Create XX (1?) new Nomad Servers
- [ ] Review https://github.com/holochain/wind-tunnel-runner-status-dashboard/issues/11 and implement if necessary.
- [ ] `bootstrap_expect` is increased to improve robustness