feat(gluetun): add inputPorts & handle common usecase (#774)

**Description**
This implement idea by @stavros-k in #771 and also add logic to detect
when user has enable qbitportforward, and automatically add gluetun
control port to inputPorts as well. Thank you stavros for help!

⚒️ 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

**🧪 How Has This Been Tested?**
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Please describe the tests that you ran to verify your changes. Provide
instructions so we can reproduce. Please also list any relevant details
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**📃 Notes:**
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**✔️ Checklist:**

- [X] ⚖️ My code follows the style guidelines of this project
- [X] 👀 I have performed a self-review of my own code
- [X] #️⃣ I have commented my code, particularly in hard-to-understand
areas
- [ ] 📄 I have made corresponding changes to the documentation
- [ ] ⚠️ My changes generate no new warnings
- [ ] 🧪 I have added tests to this description that prove my fix is
effective or that my feature works
- [X] ⬆️ 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):` or `chore(chart-name):`

**➕ 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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---------

Co-authored-by: Stavros Kois <[email protected]>
Co-authored-by: Kjeld Schouten <[email protected]>

library/common/Chart.yaml

@@ -15,7 +15,7 @@ maintainers:
 name: common
 sources: null
 type: library
-version: 20.3.1
+version: 20.3.2
 annotations:
   artifacthub.io/category: "integration-delivery"
   artifacthub.io/license: "BUSL-1.1"

library/common/templates/addons/vpn/_gluetunContainer.tpl

@@ -46,7 +46,9 @@ env:
 {{- end }}
   FIREWALL: "on"
   FIREWALL_OUTBOUND_SUBNETS: {{ $excludednetworks | quote }}
-  FIREWALL_INPUT_PORTS: {{ $.Values.service.main.ports.main.port }}
+{{- $inputPorts := (list $.Values.service.main.ports.main.port) -}}
+{{- $inputPorts = concat $inputPorts $.Values.addons.vpn.inputPorts | mustUniq }}
+  FIREWALL_INPUT_PORTS: {{ join "," $inputPorts }}
 {{- else }}
   FIREWALL: "off"
 {{- end }}

library/common/values.yaml

@@ -1003,6 +1003,9 @@ addons:
     excludedNetworks_IPv4: []
     excludedNetworks_IPv6: []
 
+    ## For Gluetun to enable kubernetes network communication
+    inputPorts: []
+
   # -- The common library supports adding a code-server add-on to access files. It can be configured under this key.
   # @default -- See values.yaml
   codeserver: