clustertool(feat): etcd metrics (#34583)

**Description**
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In the kube-prometheus-stack included in clustertool, `etcd dashboard`
is added automatically to the grafana dashboard.
To get this dashboard working you need to scrape correctly the metrics.
This can be done with multiple possibilities. I tested two.

1. The easiest option, which is this PR. It exposes the metrics on the
standard port used by the kube-prometheus-stack: 2381.
Disadvantage you can see the metrics via each computer on the same
network as it is just plain http page.

2. A more difficult option. You need to add to the kube-prometheus-stack
the certificates via a `secret` and set the correct ports.
If you are interested, that can be seen with this PR on my own cluster.
a923e4c0e4

Option 2 seems not to be implemented for me in clustertool, so therefore
a PR for option 1.
Up to here if it something OK to include like this.

⚒️ Fixes  # <!--(issue)-->

**⚙️ Type of change**

- [x] ⚙️ Feature/App addition
- [ ] 🪛 Bugfix
- [ ] ⚠️ Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] 🔃 Refactor of current code
- [ ] 📜 Documentation Changes

**🧪 How Has This Been Tested?**
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Made a new TEST Cluster bootstrap with this patch added. That went OK.
Happy to test again when a new clustertool version will be released.

**📃 Notes:**
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**✔️ Checklist:**

- [ ] ⚖️ My code follows the style guidelines of this project
- [ ] 👀 I have performed a self-review of my own code
- [ ] #️⃣ I have commented my code, particularly in hard-to-understand
areas
- [ ] 📄 I have made changes to the documentation
- [ ] 🧪 I have added tests to this description that prove my fix is
effective or that my feature works
- [ ] ⬆️ I increased versions for any altered app according to semantic
versioning
- [x] I made sure the title starts with `feat(chart-name):`,
`fix(chart-name):`, `chore(chart-name):`, `docs(chart-name):` or
`fix(docs):`

**➕ App addition**

If this PR is an app addition please make sure you have done the
following.

- [ ] 🖼️ I have added an icon in the Chart's root directory called
`icon.png`

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clustertool/embed/generic/patches/controlplane.yaml

@@ -10,6 +10,9 @@ cluster:
   controllerManager:
     extraArgs:
       bind-address: 0.0.0.0
+  etcd:
+    extraArgs:
+      listen-metrics-urls: http://0.0.0.0:2381
   proxy:
     extraArgs:
       metrics-bind-address: 0.0.0.0:10249