feat(ingressAdvanced): use tc-opencors-chain if allow-cors is enabled (#13240)

**Description**
<!--
Please include a summary of the change and which issue is fixed. Please
also include relevant motivation and context. List any dependencies that
are required for this change.
-->
⚒️ Allows for the optional use of the existing Traefik CORS setup for
Apps as CORS is required to use the official [jellyfin-vue
client](https://github.com/jellyfin/jellyfin-vue). Has been updated to
rely on https://github.com/truecharts/library-charts/pull/530

**⚙️ Type of change**

- [ ] ⚙️ Feature/App addition
- [x] 🪛 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?**
Manually edited the chart's files on my own TrueNas Scale Server.
Checked that jellyffin was using the tf-opencors-chain in Traefik rather
than basic-chain and ensured I could connect to jellyfin via a custom
app of [jellyfin-vue client](https://github.com/jellyfin/jellyfin-vue)
when the added config was enabled but not if disabled.

<img width="447" alt="Evidence of the correct chain being used in
Traefik"
src="https://github.com/truecharts/charts/assets/9092863/19a44a4e-fe95-4659-998b-753f4c4dbb4b">
<br>
<img width="213" alt="Added config option"
src="https://github.com/truecharts/charts/assets/9092863/a254c469-add2-49bf-85da-d0d17b371d7a">



**📃 Notes:**
<!-- Please enter any other relevant information here -->
This PR uses the same cors middleware setup as the existing
[audiobookshelf](https://github.com/truecharts/charts/tree/eec761785c474f47dc76124f0d2491d16bf60715/charts/stable/audiobookshelf)
app to ensure conistancy. While it may be expected that the
`tf-opencors-headers` middleware could be added within the UI this
unfortunately results in the `Access-Control-Allow-Origin` header still
being missing as the common chain conflicts.

**✔️ 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
- [x] ⚠️ My changes generate no new warnings
- [ ] 🧪 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

**➕ App addition**

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

- [ ] 🪞 I have opened a PR on
[truecharts/containers](https://github.com/truecharts/containers) adding
the container to TrueCharts mirror repo.
- [ ] 🖼️ I have added an icon in the Chart's root directory called
`icon.png`

---

_Please don't blindly check all the boxes. Read them and only check
those that apply.
Those checkboxes are there for the reviewer to see what is this all
about and
the status of this PR with a quick glance._

---------

Signed-off-by: Michael Walter Van Der Velden <mikevdv@vandie.co.uk>

charts/stable/jellyfin/values.yaml

@@ -97,4 +97,4 @@ workload:
 
 # -- enable Jellyfin autodiscovery on LAN
 autodiscovery:
-  enabled: false
+  enabled: false

templates/questions/ingress/ingressAdvanced.yaml

@@ -12,6 +12,12 @@
                         default: websecure
                         show_if: [["advanced", "=", true]]
                         required: true
+                    - variable: allowCors
+                      label: "Allow Cross Origin Requests"
+                      schema:
+                        type: boolean
+                        show_if: [["advanced", "=", true]]
+                        default: false
                     - variable: ingressClassName
                       label: (Advanced/Optional) IngressClass Name
                       schema:

templates/questions/ingress/ingressList.yaml

@@ -27,6 +27,12 @@
                 schema:
                   type: string
                   default: ""
+              - variable: allowCors
+                label: "Allow Cross Origin Requests"
+                schema:
+                  type: boolean
+                  show_if: [["advanced", "=", true]]
+                  default: false
               - variable: hosts
                 label: Hosts
                 schema: