feat: customize init command (#166)

add feature to customize the reach gitea commands.

See: https://gitea.com/gitea/helm-actions/src/branch/feat/customize-init-command/docs/connectionCommandOverride.mdReviewed-on: https://gitea.com/gitea/helm-actions/pulls/166
Co-authored-by: Daan <dselen@nerthus.nl>

docs/connectionCommandOverride.md

@@ -0,0 +1,48 @@
+# Using a custom connectionCommand
+
+By default, before the container starts it tries to reach the given giteaRootURL.  
+Normally this is done by the busybox image using the wget binary.  
+
+However, due to [Issue #162](https://gitea.com/gitea/helm-actions/issues/162) there has been a change made where we can customize that command.  
+
+Using the `values.yaml` file by default it calls `wget --spider --no-check-certificate <your giteaRootURL>` with a timeout of 10 seconds.  
+But with a custom init section like detailed below we can make our check compliant with whatever certificate you have.  
+
+Assuming:
+```yaml
+enabled: true
+giteaRootURL: https://gitea.com
+existingSecret: foo
+existingSecretKey: bar
+
+init:
+  image:
+    registry: ""
+    repository: alpine
+    # Overrides the image tag whose default is the chart appVersion.
+    tag: "3.24"
+    digest: ""
+    pullPolicy: IfNotPresent
+    fullOverride: ""
+
+  connectionCommandOverride: "curl -I"
+  preConnectionCommandOverride: "apk add curl"
+```
+
+This now creates the following template section:
+
+```yaml
+        - name: init-gitea
+          image: "alpine:latest"
+          command:
+            - sh
+            - -c
+            - |
+              apk add curl
+              echo 'Trying to reach Gitea on https://gitea.com'
+              until timeout 10 curl -I https://gitea.com; do
+                sleep 3
+                echo "Trying again in 3 seconds..."
+              done
+              echo "Gitea has been reached!"
+```