First sidecar module: OpenTelemetry (#8013)

* remove opentelemetry from main nginx image

* add opentelemetry sidecar image

* handle extra modules in helm chart

* fix running helm chart

* mount the modules volume in the init container

* merge the mounted folder

* fix the otel image

* fix licence year

* fix cloudbuild image

* use the same nginx version as in the main image

* only retrieve /etc/nginx/modules for now

charts/ingress-nginx/ci/daemonset-extra-modules.yaml

@@ -0,0 +1,10 @@
+controller:
+  kind: DaemonSet
+  image:
+    repository: ingress-controller/controller
+    tag: 1.0.0-dev
+  service:
+    type: ClusterIP
+  extraModules:
+    - name: opentelemetry
+      image: busybox