fix(docs): service integrations (#37066)

**Description**
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With the new common this annotation was not set anymore:
```
-  annotations:
   -    metallb.io/loadBalancerIPs: ${IP_BLOCKY}
```
Try to modify the docs to emphasize the integrations

⚒️ Fixes  # <!--(issue)-->

**⚙️ Type of change**

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

**🧪 How Has This Been Tested?**
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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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website/src/content/docs/guides/add-service.md

@@ -19,6 +19,10 @@ service:
     # only needed for loadBalancer
     loadBalancerIP: "192.168.178.11"
     type: "LoadBalancer"
+    # integration needed to assign the specific loadBalancerIP via metallb
+    integrations:
+      metallb:
+        enabled: true
     ports:
       web:
         enabled: true
@@ -40,6 +44,42 @@ In most charts there are already predefined services. You can change them to you
 Please be aware that most apps already have a primary service named `main` and at least 1 primary is required.
 It's also important to note that all services added by the end user should set `enabled` on all ports and services to `true`.
 
+### Service intergrations
+
+For each service you can add a specific integration. Metallb, Cilium or Traefik can be choosen. 
+In above example metallb integration is used, to get the correct metallb annotation for the ip assignment.
+
+Integrations can be enabled as follow:
+
+**Metallb**
+```yaml
+service:
+  myservice:
+    integration:
+      metallb:
+        enabled: true
+          sharedKey: ""  ## Optional to set shared key manually, otherwise it is set to $namespace as standard
+```    
+
+**Cilium**
+```yaml
+service:
+  myservice:
+    integration:
+      cilium:
+        enabled: true  
+          sharedKey: ""  ## Optional to set shared key manually, otherwise ignored (namespace sharing)
+```
+
+**Treafik**
+```yaml
+service:
+  myservice:
+    integration:
+     traefik:
+      enabled: true
+```
+
 ## More info
 
 For more info, check out the common-chart [service options](/common/service/)