Adding Gitea Virtual Service to Big Bang example (#1475)

## Description

I thought I would expand the example by showing a relevant and useful
addition. Since Gitlab is typically deployed with Big Bang, this would
give somewhat of an equivalent feel to be able to not have to worry
about setting up a proxy forward for the service for Gitea.

## Related Issue

N/A

## Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Other (security config, docs update, etc)

## Checklist before merging

- [ ] Test, docs, adr added or updated as needed
- [ ] [Contributor Guide
Steps](https://github.com/defenseunicorns/zarf/blob/main/CONTRIBUTING.md#developer-workflow)
followed

examples/big-bang/virtualservices/gitea.yaml

@@ -0,0 +1,16 @@
+apiVersion: networking.istio.io/v1alpha3
+kind: VirtualService
+metadata:
+  name: gitea
+  namespace: zarf
+spec:
+  gateways:
+    - istio-system/public
+  hosts:
+    - gitea.###ZARF_VAR_DOMAIN###
+  http:
+    - route:
+        - destination:
+            host: zarf-gitea-http.zarf.svc.cluster.local
+            port:
+              number: 3000

examples/big-bang/zarf.yaml

@@ -27,3 +27,12 @@ components:
           - config/loki.yaml
           # Values are merged in order, so this would override the above and disable everything if uncommented
           # - config/disable-all.yaml
+  - name: gitea-virtual-service
+    description: >
+      Expose the internal Zarf Gitea server through the Big Bang Istio deployment via a virtual service.
+      (only applies if you are using the Zarf-provided Gitea deployment - not an externally configured git host)
+    manifests:
+      - name: gitea
+        namespace: zarf
+        files:
+          - virtualservices/gitea.yaml